MXPA00010690A - New use - Google Patents

Abstract

The present invention relates to pharmaceutical compositions comprising a positive modulator of a nicotinic receptor agonist, said positive modulator having the capacity to increase the efficacy of the said nicotinic receptor agonist.

Description

PHARMACEUTICAL COMPOSITIONS THAT COMPRISE A POSITIVE MODULATOR OF AN AGONIST OF RECEPTORS NICOTINIC Technical Field The present invention relates to pharmaceutical compositions comprising a positive modulator of a nicotinic receptor agonist, this positive modulator has the ability to increase the efficacy of this nicotinic receptor agonist.

BACKGROUND OF THE INVENTION Cholinergic receptors normally bind to the endogenous neurotransmitter acetylcholine (ACh), and therefore, activate the opening of the gates of the ion channels. ACh receptors in the nervous system of mammals can be divided into the muscarinic (mAChR) and nicotinic (nAChR) subtypes based on muscarin and nicotine agonist activities, respectively. Nicotinic acetylcholine receptors are ion channels of ligands controlled by channels with gates containing 5 subunits (for reviews, see Colquhon et al. (1997) Advances in Pharmacology 39, 191-220; Williams Ref: 124364 et al. 1994) Drug News &Perspectives 7, 205-223; Doherty et al. (1995) Annual Reports in Medicinal Chemistry 30, 41-50). The members of the nAChR gene family have been divided into two groups based on their sequences; the members of a group are considered ß subunits, while in the second group they are classified as subunits a (for reviews, see Karlin & A abas (1995) Neuron 15, 1231-1244; Sargent (1993) Ann. Rev. Neurosci., 16, 403-443). Three of the subunits a, a7, a8, and a9, form functional receptors when expressed alone and therefore, presumably form homoligomeric receptors. A model of the transitional halosteric state of the nAChR involves at least a state of rest, an active state and a state of closed * insensitized channels (Williams et al., Supra, Karlin &Ákabas, supra). Therefore, the different nAChR ligands can differentially stabilize the conformational state to which they agglutinate preferentially Ach agonists and nicotine- (-) stabilize the active and desensitized states.

Changes in nicotinic receptor activity are implicated in a variety of diseases. Some of these, for example, myasthenia gravis and ADNFLE (autosomal dominant nocturnal epilepsy of the frontal lobe) (Kuryatov et al. (1997) J. Neurosci 17 (23): 9035-47), are associated with reductions in activity of nicotinic transmission, either through a decrease in the number of receptors or an increase in desensitization, and is a process by which the receptors become insensitive to the agonist. The reduction in nicotinic receptors also has the hypothesis of mediating the cognitive deficiencies that are observed in diseases such as Alzheimer's disease and schizophrenia (Williams et al., Supra). The effects of nicotine in tobacco are also mediated by nicotinic receptors. The increased activity of nicotinic receptors can reduce the desire to smoke. The use of compounds that bind the nicotinic acetylcholine receptors, during the treatment of a range of disorders involving a reduced cholinergic function such as in Alzheimer's disease, cognitive disorders on attention, attention deficit disorders due to hyperactivity, anxiety, Depression, cessation of smoking, neuroprotection, schizophrenia, analgesia, Tourette's syndrome, and Parkinson's disease are discussed in McDonald et al. (1995) 'Nicotinic Acetylcholine Receptors: Molecular Biology, Chemistry and Pharmacology, "Chapter 5 in Annual Reports in Medicinal Chemistry, vol 30, pp. 41-50, Academic Press Inc., San Diego, CA, and in Williams et al. . (1994) 'Neuronal Nicotinic Acetylcholine Receptors. " Drug News & Perspectives, vol. 7, pp. 205-223. However, treatment with nicotinic receptor agonists that act on the same site as ACh is problematic because ACh not only activates, but also blocks receptor activity by processes that include numbing (for a review, see Ochoa et al (1989) Cellular and Molecular Neurobiology 9, 141-178) and a non-competitive blockade (open channel block) (Forman &; Miller (1988) Biophysical Journal 54 (1): 149-58). In addition, prolonged activation appears to induce long-term inactivation. Therefore, it is expected that ACh agonists reduce activity or intensify it. In general, in nicotinic receptors and, of particular interest, in the a7 nicotinic receptor, desensitization limits the duration of the current during the application of the agonist.

Brief Description of the Figures Figure 1 Model of the current recording lines caused by the agonist, which represents the determination of the increase in the efficiency of the agonist by determining the amplitude of the current. The bars show the duration of the application of the compounds.

Figure 2 Model of the current recording lines caused by the agonist, which represents the determination of the increase in the efficiency of the agonist by determining the * area under the curve. "The arrow indicates the superposition of the ACh current and the modulator current + Ach. The bars show the duration of the application of the compounds.

Figure 3 Effect of 5-hydroxyindole on ACh activity on the nicotinic-a7 receptor. The current value of 100% is extrapolated to a maximum of the ACh curve. (•) ACh (O) ACh + 0.5 mM 5-hydroxyindole Figure 4 Effect of 5-hydroxyindole on ACh activity in the nicotinic-a7 receptor (human, rat and chicken) that is expressed in the Xenopus oocyte.

Figure 5 Effect of 5-hydroxyindole on Ach (open staples) and (-) - Spiro [1-Azabicyclo [2.2.2.] Octan-3, 5 * -Oxazolidin] -2 * -Ona (filled staples) of activity in the nicotinic-a7 receptor that is expressed in Xenopus oocytes.

Figure 6 Effect of the nAChR modulator of a7 on agonist activity when quantified by a flow of Ca2 + through nAChR of a.7 which is expressed in HEK-293 cells. The agonist is represented by the (-) - Spiro [1-Azabicyclo [2.2.2. ] 0ctan-3, 5 * -Oxazolidin] -2 * -Ona.

Detailed Description of the Invention It has been surprisingly discovered that certain compounds, for example 5-hydroxyindole (5-OHi), can enhance the efficacy of agonists at nicotinic receptors. This increase in effectiveness can be greater than two times. It is believed that compounds having this type of action (hereinafter referred to as 'positive modulators') are particularly useful for the treatment of conditions associated with reductions in nicotinic transmission.In a therapeutic setting, these compounds can restore normal interneuronal communication without affecting the temporal profile of activation, and do not produce long-term inactivation, as may occur with prolonged application of the agonist • The presence of this efficacy-enhancing activity can not be predicted in the technique Albuquerque et al., report on another halosteric site in nicotinic receptors, which they call a non-competitive agonist site *. Compounds that act on this site are also called 'halosterically potentiating ligands' (APL). Compounds that appear to act on this site include several cholinesterase inhibitors, codeine, and 5-HT. this non-competitive agonist site "does not affect the maximum response level for ACh; and shifts the dose-response curve to the left "(Maelicke &Albuquerque (1996) DDT, vol.1, 53-59) In a specific distinction, the compounds acting at the discovered site increase the maximum response of the ACh (its effectiveness) Another distinction between APLs and the present invention is the effect that modulators have on the total current (the way in which it is quantified by the area under the curve) in the presence of a saturated concentration of the agonist. have little or no effect on the area under the curve of nAChR 7 that is expressed in oocytes, increases of 8-10% have been observed in the area under the curve in one application of the agonist for one second. -OHi causes a large increase in the area under the curve (increase ~ 400%) under the same conditions (see Figure 4, outstanding record line) .The specificity of the effect within the family of nicotinic receptors is even another characteristic. distinguishing characteristic among the APLs of the invention. APL exert their positive modulatory effect on all nicotinic receptors that are analyzed, including those of the muscular type (alßde). In some non-nicotinic receptors, compounds have been found that can decrease the desensitization of the receptors. In the excitatory receptors of AMPA-type amino acids, compounds such as cyclothiazide, some lectins such as wheat germ agglutinin, piracetam-like notrópicos, and AMPAcinas have been shown to decrease desensitization (Partin et al., 1993). Neuron 11, 1069-1082). It has been reported that glycine reduces the desensitization of the excitatory receptors of NMDA-type amino acids (Mayer et al. (1989) Nature 338, 425-427). However, it has been found that compounds that decrease desensitization in a group of receptors, in general, do not have the same effect on other groups of receptors. For example, cyclothiazide has little or no effect on the NMDA and KA subtypes of glutamate receptors (Partin et al. (1993) Neuron 11, 1069-1082); even more, it is discovered that cyclothiazide blocks 5-HT3 receptors (D. A. Gurley, unpublished results). Glycine has no effect on 5-HT3 receptors (Gurley and Lanthorn, (in press) Neurosci. Lett.). This site was discovered by using a compound (5-OHi) which is known to decrease desensitization at the 5-HT3 receptor (Kooy an, A. R. et al. (1993) British Journal of Pharmacology 108, 287-289). However, only another compound has been reported that produces or increases activity at the 5-HT3 receptor, 5-HT itself, because it increases the activity of nicotinic receptors (Schrattenholz et al. (1996) Molecular Pharmacology 49, 1-6) although this activity has never been reported in the Xenopus oocytes. Most agonists at the 5-HT3 receptor do not have any activity or are nicotinic receptor agonists (unpublished results). In addition, current inventors are unable to reproduce the discovery that 5-HT increases activity in a nicotinic receptor. Therefore, the intensifying effect of 5-OHi on nicotinic receptors could not have been predicted. Accordingly, the present invention provides a first aspect of a pharmaceutical composition comprising a positive modulator of a receptor agonist. Nicotinic together with a pharmaceutically acceptable carrier, this positive modulator has the ability to increase the efficacy of this agonist receptor. For the purposes of the present invention, the term "positive modulator" or "positive modulator of a nicotinic receptor agonist" is to be understood as a compound that has the ability to increase the maximum efficacy of a nicotinic receptor agonist.

It is understood that the invention includes compositions comprising, a positive modulator as the sole active substance, and therefore modulating the activity of endogenous agonists of nicotinic receptors, or a positive modulator in combination with a nicotinic receptor agonist. Therefore, these pharmaceutical compositions containing a positive modulator of a nicotinic receptor agonist can, in addition, comprise a nicotinic receptor agonist. In a preferred form of the invention, this positive modulator is 5-hydroxyindole. In another preferred form of the invention, this nicotinic receptor agonist is a nicotinic receptor agonist-a.7. The example of the nicotinic receptor agonist-a7 is (-) - Spiro [1-Azabicyclo [2.2.2. ] Octan-3, 5 * -Oxazolidin] -2 * -Ona. Various nicotinic receptor agonists-a7 are known in the art, for example from WO 96/06098, WO 97/30998 and WO 99/03859. In another aspect, the invention provides a method for the treatment of a condition associated with reduced nicotine transmission, and administering to a patient in need of this treatment, a medically effective amount of a positive modulator of a nicotinic receptor agonist. , this positive modulator has the ability to increase the efficacy of this nicotinic receptor agonist. It is understood that the methods of treatment of this invention include as the sole active substance, either a positive modulator which therefore modulates the activity of the endogenous agonists of the nicotinic receptors, or a positive modulator administered in conjunction with an agonist of the nicotinic receptors. In a preferred form of the invention, this treatment method includes the 5-hydroxyindole positive modulator. In another preferred form of the invention, this method of treatment includes a nicotinic receptor agonist which is an agonist of nicotinic receptors-a7. The example of the nicotinic receptor agonist-a7 is (-) - Spiro [1-Azabicyclo [2.2.2. ] Octan-3, 5 * -Oxazolidin] -2 * -Ona. Various nicotinic receptor agonists-a7 are known in the art, for example from WO 96/06098, WO 97/30998 and WO 99/03859. Another aspect of the invention is the use of a pharmaceutical composition, according to the invention, for the preparation of a medicament for the treatment or prophylaxis of a condition associated with reduced transmission of nicotinic receptors, condition associated with reduced nicotinic density which may be one of the diseases associated below or conditions comprising administering to a patient a therapeutically effective amount of the compounds according to the invention. It is understood that the use includes compositions comprising either a positive modulator as the sole active substance, therefore they modulate the activity of the endogenous agonists of nicotinic receptors, or a positive modulator in combination with a nicotinic receptor agonist. Therefore, this use of the pharmaceutical compositions containing a positive modulator or a nicotinic receptor agonist can further comprise a nicotinic receptor agonist.

A preferred form of the invention, the use comprises the 5-hydroxyindole positive modulator. In another preferred form of the invention, the use of this nicotinic receptor agonist is represented by a nicotinic-a7 receptor agonist. The example of a nicotinic receptor agonist-a7 is (-) - Spiro [1-Azabicyclo [2.2.2. ] Octan-3, 5 * -Oxazolidin] -2 * -Ona. Various nicotinic receptor agonists-a7 are known in the art, for example from WO 96/06098, WO 97/30998 and WO 99/03859. Examples of diseases or conditions include schizophrenia, manic depression or mania, anxiety, Alzheimer's disease, learning deficiency, knowledge deficiency, attention deficit, memory loss, attention deficit disorder due to hyperactivity, Parkinson's disease, Huntington's disease, Tourette's syndrome, temporary imbalance caused by travel, and addiction to nicotine (which includes that resulting from exposure to nicotine-containing products). It is understood that this positive modulator can be administered either for the purpose of acting on the endogenous agonists of the nicotinic receptors, or in combination with an exogenous agonist of the nicotinic receptors. This additional aspect of the invention relates to a pharmaceutical composition for treating or preventing a condition or disorder as exemplified above that arises due to dysfunction of neurotransmission of the nicotinic acetylcholine receptor in a mammal, preferably in a human, compositions comprising either a positive modulator as the sole active substance, therefore modulate the activity of the endogenous agonists of nicotinic receptors, or a positive modulator in combination with a nicotinic receptor agonist. Therefore, this use of the pharmaceutical compositions containing a positive modulator of a nicotinic receptor agonist can further comprise an effective nicotinic receptor agonist to treat or prevent this disorder or condition, in an inert and pharmaceutically acceptable carrier. For the aforementioned uses, the dose administered obviously varies depending on the composition used, the mode of administration and the treatment desired. However, in general, satisfactory results are obtained when the active components are administered at a daily dose of about 0.1 mg to about 20 mg per kg of the body weight of the mammal, preferably given in divided doses of 1 to 4 times a day. day or in the form of prolonged release. For man, the total daily dose is in the range from about 5 mg to 1,400 mg, more preferably from 10 mg to 100 mg, and the unit dosage forms are suitable for oral administration and comprise from 2 mg to 1,400 mg of the active components mixed with a solid or liquid pharmaceutical carrier or a diluent. The compositions mentioned above can be used by themselves or in the form of medicinal preparations suitable for enteral, parenteral, oral, rectal or nasal administration. Examples of suitable diluents and carriers are: for tablets and dragees: lactose, starch, talc, stearic acid; -for capsules: tartaric acid or lactose; -for injectable solutions: water, alcohols, glycerin, vegetable oils; -for suppositories: oils or natural or hardened waxes. Also provided is a process for the preparation of this pharmaceutical composition comprising mixing the ingredients simultaneously or sequentially. In another aspect, the invention provides a method for identifying a positive modulator of a nicotinic receptor agonist. The compounds are considered 'positive modulators' if, in the presence of saturation concentrations of the nAChR agonist of ACh a7, a current exceeding 200% of the control current (100% enhancement) is caused when quantified from the reference line to the peak (see experimental methods). The control current is defined as the current elicited by the agonist in the absence of a modulator. A saturation concentration of ACh is defined as 10 times the EC5o for the specific type of nAChRa7 that is used. The EC50 is defined as the concentration that causes a maximum average response. The EC50 values for the nAChRa7 subtypes typically range from 100-300 μM (Bertrand et al. (1992) Neuroscience Letters 146, 87-90; Peng et al. (1994) Molecular Pharmacology 45, 546-554). In addition, the compounds are considered 'positive modulators' if, in the presence of saturation conditions of the agonist, the total current through the receiver (flow) exceeds the 200% of the control current. One quantification of the total current is the area below the curve (line recording the current during an application of the agonist) Accordingly, the method according to the invention for identifying a positive modulator of a nicotinic receptor agonist, can comprise steps of (a) expressing a nicotinic receptor on the surface of a cell; (b) contacting this nicotinic receptor with a compound known to be an agonist of nicotinic receptors and a compound to be analyzed according to its positive odulator activity; c) determine if the compound to be analyzed exhibits a positive modulation on the effect of this nicotinic receptor agonist, resulting in a current amplitude (quantified from the reference line to the peak) or total current (quantified as the area under the curve for the current recording line) greater than 200% of the control (100% enhancement) The cell can be an ooci Xenopus, a HEK-293 cell or a cultured neuron. The nicotinic receptor can either be a nicotinic receptor of human, rat, chicken, mouse or bovine. Another aspect of the present invention relates to a method for identifying a positive modulator of a nicotinic receptor agonist, the nicotinic receptor is a nicotinic-a receptor. In yet another aspect, the invention provides a method for identifying a compound that is a nicotinic receptor agonist, this method comprises the steps of (a) expressing a nicotinic receptor on the surface of a cell; (b) contacting this nicotinic receptor with a compound to be analyzed for the activity of the nicotinic receptor agonist, in the presence of a positive modulator of a nicotinic receptor agonist; and (c) determining whether the compound to be analyzed exhibits the activity of the nicotinic receptor agonist. The cell can be a Xenopus oocyte, a HEK-293 cell or a cultured neuron. The nicotinic receptor can be a nicotinic receptor either human, rat, ovine, murine or bovine. It is understood by the skilled person that, 'the activity of the nicotinic receptor agonist' can be determined by methods that are known in the art, such as those methods described below in the 'Experimental Methods' section. In another aspect of the present invention, with regard to the method for identifying a compound that is a nicotinic receptor agonist, the nicotinic receptor is a nicotinic-a receptor.

Experimental Methods (a) Recording the current in a Xenopus oocyte The Xenopus oocyte provides a powerful means to evaluate the function of proteins through the subunits of the ion channels of the ligands controlled by channels with gates. Injection of RNA transcribed from the cDNA clones encoding the appropriate subunits of the receptor, or injection of the cDNA where the coding sequence is placed 3 'of a promoter, results in the appearance of ligand ion channels controlled by channels with gates on the surface of the oocyte (see, for example, Boulter et al. (1987) Proc. Nati. Acad. Sci. USA 84, 7763-7767). Accordingly, a convenient technique for assessing the enhancement of nicotinic efficacy is a record of Xenopus oocytes expressing for nicotinic-a7 receptors from a cRNA, which utilizes a 2-electrode voltage clamp. Xenopus laevis frogs (Xenopus I, Kalamazoo, MI) are anesthetized using 0.15% tricaine. The oocytes are removed to an OR2 solution (82 mM NaCl, 2.5 mM KCl, 5 mM HEPES, 1.5 mM NaH2P04, 1 mM MgCl2, 0.1 mM EDTA; pH of 7.4). The oocytes are extracted from the follicles by incubation in 25 ml of OR2 containing 0.2% collagenase 1 A (Sigma) twice for 60 minutes on a platform that vibrates at 1 Hz and stored in an L-15 medium. Leibovitz (50 μg / ml gentamicin, 10 units / ml penicillin, and 10 μg / ml streptomycin). Approximately 50 ng of cRNA is injected into each oocyte on the next day. The cRNA is synthesized from the cDNA using a Message Machine (acquired from Abion). The external recording solution consists of 90 mM NaCl, 1 mM KCl, 1 mM MgCl2, 1 mM BaCl2, 5 mM HEPES; pH of 7.4. A register using a two-electrode voltage fixation is carried out by using an Oocyte Fixation Amplifier (OC 725C, Warner Instrument, Hamdem, CT). Oocytes are impacted with a resistance peak of 1-2 MO when filled with 3M KCl. The registers begin when the membrane potential becomes stable at negative potentials at -20mV (resting membrane potentials are less negative when Ba ++ replaces Ca ++ in bath solutions). The membrane potential is assured at -80mV. The ACh is acquired from Sigma. The oocytes are continuously impregnated (5ml / min) with the registration solution with, or without ACh. The current amplitude is quantified from the reference line to the peak. The EC50 values, maximum effect, and slope are estimated by fitting the logistic equation data when using a GraphPad Prism (GraphPad Software, Inc., San Diego, CA): Increases in agonist efficiency caused by a positive modulator can be calculated in two ways: (1) As a percentage of the amplification of current amplitude that is defined as 100 (Im-Ic) / Ic where Im is the current amplitude in the presence of a modulator and the Ic is the current in the absence of a modulator (Figure 1). (2) As a percentage of enhancement of the 'area under the curve' of an agonist record line The area under the curve is a common representation of the total flow of ions through the channel (Figure 2). shown in Figure 2, although the amplitude of the current does not increase, the area under the curve is potentiated by approximately 100% over the control for the duration of the application of the agonist. (b) Imaging of the Ca + 2 flux Imaging of the Ca + 2 flux by nAChRa7 receptors that are transiently expressed in a cell line is another means of evaluating modulator activity. Cells that express for a7 receptors (eg HEK-293 cells or cultured cell neurons) are cultured to come together in 96-well plates and loaded with fluo-3, a fluorescent indicator of calcium. To detect the odulatory activity of al, the 96-well plate is placed in a fluorescent imaging plate (FLIPR) and the compounds to be analyzed together with an a7 agonist are applied simultaneously in the wells. Activation of the receptor is quantified by the influx of calcium to the cells that is quantified by the increase in fluorescence intensity in each well, which is recorded simultaneously by the FLIPR. A modulatory effect is determined by the increase in fluorescence over that of the agonist alone. similarly, to annex the agonist activity of nAChRa7, the compounds to be analyzed together with a modulator a7 are applied simultaneously in the wells. Activation of the receptor is quantified by the influx of calcium into the cells which is quantified by increasing the fluorescence intensity of each well, which is recorded simultaneously by FLIPR. An agonist effect is determined by the increase in fluorescence over that of the modulator only. Cell culture neurons are prepared according to the following method: 18-day-old Sprague-Dawley rat (E-18) fetuses are removed aseptically from the pregnant female and sacrificed and the frontal cortex of the brains, their meninges are stripped, the clean bark is placed in cold HBSS. If the hippocampus is desired, the hippocampus is dissected from the cortex and then placed in cold HBSS. The tissues are mechanically dispersed, and washed once in HBSS (200 g for 30 minutes at 4 ° C) and resuspended in a modification of Sato's medium supplemented with glutamine, antibiotics, potassium chloride, insulin, transferrin, selenium, and 5% thermoinactivated fetal bovine serum (FBS, free of endotoxins) and placed in plates in each of the 24 wells of the plate (they are coated with poly-L-lysine). The wells may contain glass covers that are also covered with PLL. The plates are incubated at 37 ° C in a C02 incubator. After a period of 24 hours, the medium is removed, fresh media is added and the cells are allowed to grow for a period of 11 days, and are fed when necessary.

EXAMPLE 1 Changes in the efficacy of nicotinic agonists are evaluated by quantifying the combined effects of a nicotinic agonist with the test compounds. In general, the protocol consists of a pre-treatment with the test compound plus a simultaneous application of the agonist and the test compound. The 5-hydroxyindole is analyzed at 500 μM against a range of ACh concentrations. The ACh first analyzes itself so that an EC50 and a maximum response can be determined. Then the same concentrations of Apply, together with 5-OH-indole. The results (Figure 3) are that the maximum response to ACh is increased (maximum amplitude increases 2 times). The effect of 5-OHi (0.5 mM) on the 'area under the curve' is determined for the saturation concentration of the agonist (3 mM ACh.) 5-OHi causes a large increase in the area under the curve ( increase of approximately 400%) (Figure 4) When applied by itself, 5-hydroxyindole does not induce a current in oocytes injected with cRNA for nicotinic a7 receptors.

EXAMPLE 2 The effect of 5-hydroxyindole on various nicotinic agonists is analyzed. The increase in efficacy allowed by 5-hydroxyindole is observed in all nicotinic agonists that are analyzed, for example (-) - Spiro [1-Azabicyclo [2.2.2.] 0ctan-3, 5 * -Oxazolidin] - 2 * -Ona (Figure 5). The hollow columns of Figure 5 to which a current is caused by ACh (3 mM) with (+) and without (-) the modulator. The filled columns of Figure 5 to which a current is caused by the nicotinic agonist designated AR-R 17779 (100 μM) with (+) and without (-) a modulator. The modulator in this case is 1 mM of 5-OHi. Compounds analyzed with similar results include (-) nicotine and choline (data not shown).

Therefore the effect seems to be general for any cholinergic agonist.

EXAMPLE 3 The increase in efficacy allowed by 5-hydroxyindole is not observed in any other nicotinic receptor, for example mouse muscle nicotinic receptors.

EXAMPLE 4 A series of related compounds is analyzed for the positive modulation of ACh activity. Only some compounds retain the effectiveness of the intensifying activity. In particular, serotonin (5-HT) does not increase efficacy. This preliminary analysis of close analogues indicates a rather close structure-activity relationship, suggesting a selective site of action.

EXAMPLE 5 The effect of the nAChRa7 modulator on agonist activity is quantified by the flow of Ca2 + by nAChRa7 which is expressed in HEK-293 cells. The nicotinic agonist (-) - Spiro [1-Azabicyclo [2.2.2.] Octan-3, 5 * -Oxazolidin] -2 * -One is used. The results are shown in Figure 6. No discernable signal is obtained in the presence only of the agonist (without modulator). In the presence of the agonist together with the modulator, a significant increase in the activity of the agonist is observed.

It is noted that in relation to this date, the best known method for the applicant to carry out the aforementioned invention, is the conventional one for the manufacture of the objects or products to which it refers.

Claims (19)

CLAIMS Having described the invention as above, the content of the following claims is claimed as property:

1. A pharmaceutical composition, characterized in that it comprises a positive modulator of a nicotinic receptor agonist together with a pharmaceutically acceptable carrier, this positive modulator has the ability to increase the efficacy of this nicotinic receptor agonist.

2. The pharmaceutical composition according to claim 1, characterized in that it also comprises a nicotinic receptor agonist.

3. The pharmaceutical composition according to claim 1 or 2, characterized in that this positive modulator is 5-hydroxyindole.

4. The pharmaceutical composition according to any of claims 1 to 3, characterized in that this nicotinic receptor agonist is an agonist of nicotinic receptors-a7.

5. A method for identifying a positive modulator of a nicotinic receptor agonist, characterized in that this method comprises the steps of (a) expressing a nicotinic receptor on the surface of a cell; (b) contacting this nicotinic receptor with a compound known to be a nicotinic receptor agonist and a compound to be analyzed for positive modulatory activity; (c) determining if the compound to be analyzed exhibits a positive modulation on the effect of this nicotinic receptor agonist.

6. A method for identifying a compound that is a nicotinic receptor agonist, this method characterized in that it comprises the steps of (a) expressing a nicotinic receptor on the surface of a cell; (b) contacting this nicotinic receptor with a compound to be analyzed for the activity of the nicotinic receptor agonist, in the presence of a positive modulator of a nicotinic receptor agonist; and (c) determining whether the compound to be analyzed exhibits the activity of the nicotinic receptor agonist.

7. A method according to claim 5 or 6, characterized in that the cell is an oocyte of Xenopus, a HEK-293 cell or a cell culture neuron.

8. A method according to claim 5 or 6, characterized in that the nicotinic receptor is a nicotinic-a7 receptor.

9. A method according to claim 5 or 6, characterized in that the nicotinic receptor is either a human, rat, chicken, mouse or bovine nicotinic receptor.

10. A compound identifiable by the method according to any of claims 5 to 7.

11. The use of a positive modulator of a nicotinic receptor agonist in the preparation of a medicament for the treatment or prophylaxis of a condition associated with reduced nicotine transmission.

12. The use of a positive modulator of a nicotinic receptor agonist together with a nicotinic receptor agonist in the development of a medicament for the treatment of a condition associated with reduced nicotine transmission.

13. The use according to claims 9 or 10, characterized in that the modulator is 5-hydroxyindole.

14. The use according to claims 9 or 10, characterized in that the nicotinic receptor agonist is an agonist of nicotinic receptors-a7.

15. The use according to any of claims 9 to 12, characterized in that it is for the preparation of a medicament for the treatment of Alzheimer's disease, attention deficit disorder due to hyperactivity, schizophrenia, anxiety or addiction to nicotine.

16. The use according to any of claims 9 to 12, characterized in that it is for the preparation of a medicament for the treatment of Alzheimer's disease.

17. The use according to any of claims 9 to 12, characterized in that it is for the preparation of a medicament for the treatment of an attention deficit hyperactivity disorder.

18. The use according to any of claims 9 to 12, characterized in that it is for the preparation of a medicament for the treatment of schizophrenia.

19. The use according to any of claims 9 to 12, characterized in that it is for the preparation of a medicament for the treatment of nicotine addiction.