Abstract:
Use of N,N-dimethyl-1-[1-(4-chlorophenyl)cyclobutyl]-3-methylbutylamine or a pharmacologically acceptable acid addition salt thereof for manufacture of a cerebral function improver for the treatment of cerebral function disorders, which is useful as an improver for cerebral function disorders such as amnestic syndrome, senile dementia and Parkinson&#39;s disease, since it can intensively activate the central nervous system, especially dopamine neuron, and also increase the spontaneous movement in human or animal.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a use of N,N-dimethyl-1-[1-(4-chlorophenyl)cyclobutyl]-3-methylbutylamine or pharmacologically acceptable acid addition salt thereof for manufacture of a cerebral function improver in the treatment of cerebral function disorders. 
     It is described that N,N-dimethyl-1-[1-(4-chlorophenyl)cyclobutyl]-3-methylbutylamine has a therapeutical effect as an antidepressant in the Japanese Unexamined Patent Publication No. 181,043 (1982). 
     In recent years, cerebral function disorders has caused public discussion in attendance on the shift to the high-aged society. The cerebral function disorders are induced by cerebrovascular diseases such as cerebral infarction, cerebral bleeding, cerebral arteriosclerosis, cerebral venous thrombosis, head injuries and the like and give a variety of symptoms as secondary diseases, for example, disturbance of consciousness, senile dementia, coma, lowering of attention, speech disorder and the like. Therefore, there are desired a drug having a high activity with little side effect for the treatment of the cerebral function disorders. 
     It has now been found that the above compound is especially useful for manufacture of a cerebral function improver in the treatment of cerebral function disorders, wherein intelectural functions in brain make lowered, such as amnestic syndrome, senile dementia and Parkinson&#39;s disease since the compound has surprisingly an intensive effect on memory and learning in preclinical studies. Accordingly, this invention has been accomplished. 
     SUMMARY OF THE INVENTION 
     In accordance with the present invention, there is provided use of N,N-dimethyl-1-[1-(4-chlorophenyl)cyclobutyl]-3-methylbutylamine or a pharmacologically acceptable acid addition salt thereof for manufacture of a cerebral function improver for the treatment of cerebral function disorders. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a graph showing the effect of the test samples on spontaneous movement in mice. 
    
    
     DETAILED DESCRIPTION 
     The compound according to the present invention may be used as a free base or an acid addition salt thereof. In the latter case, it is preferable to be in the form of pharmacologically acceptable salts, for instance, hydrochloride, sulfate, tartrate, succinate and acidic amino acid salts such as aspartate and glutamate. 
     The daily dosage of the cerebral function improver of the present invention to adults is preferably in the range of from 2 to 50 mg. Examples of the dosage form are, for instance, tablet, capsule, powder, granule, liquid preparation, parenteral injection and the like. 
     Moreover, if necessary, pharmacologically acceptable additives such as stabilizer, surface active agent preserver and flavor may be used to prepare the cerebral function improver of the present invention. 
     The cerebral function improver having the compound as an active ingredient may be suitably used for the treatment of symptons such as amnestic syndrome, disturbance of consciousness, senile dementia, coma, lowering of attention, speech disorder and the like, which are induced by the lower or disorder of cerebral function, since the compound has such an effect as activating the central nervous system through an intensive activation of dopamine neuron in addition to both norepinephrine and serotonin neuron. 
     Moreover, the cerebral function improver of the present invention can be used in the treatment of Parkinson&#39;s disease, Lennox syndrome, autism, hyperkinetic syndrome, schizophrenia and the like, based on the increase of spontaneous movement and the enhancing effect of dopamine activity. 
     The present invention is more specifically described and explained by means of the following Test Examples and Formulation Examples in which N,N-dimethyl-1-[1-(4-chlorophenyl)cyclobutyl]3-methylbutylamine hydrochloride is used as the test compound. 
     It is to be understood that the present invention is not limited to the following Examples, and various changes and modifications may be made in the invention without departing from the spirit and scope thereof. 
     TEST EXAMPLE 1 
     Action of the test samples on the memory defect artificially induced by electroconvulsive shock in mice 
     C 57 BL/6 male mice (5 week age) weighing of 19±2 g were fed for a week under the conditions of 22° to 24° C. and about 60% R.H., and subjected to the test. The test was carried out by using a box divided into two rooms (light and dark). The dark room (23.5 cm in height, 12 cm in width and 24 cm in length) was surrounded by black inner walls and provided with a stainless steel bar on the floor to give the mouse an electric shock. The light room (triangular in shape with 15 cm in height, 13 cm in bottom side length and 12 cm in oblique-side length) was surrounded by transparent walls except for the partition wall, provided with a guillotine door (5 cm in height and 3 cm in width) at the center of the partition wall, and illuminated with a 100 Watt electric bulb at a position of 50 cm above the floor. 
     The test was carried out according to the procedures as follows: 
     (1) Taming trial 
     After the mouse was put in the light room, the guillotine door was opened. When the limbs of the mouse entered into the dark room, the door was closed. After keeping the mouse for 10 seconds in the dark room, it was brought back to the home cage. 
     (2) Acquisition trial 
     The mouse was put in the light room at the time of 30 minutes after the taming trial, and then the guillotine door was opened. When the limbs of the mouse entered into the dark room, the door was closed and 0.4 mA of electric shock was applied to the limbs of the mouse for 3 seconds. Then, the mouse was brought back to the home cage. 
     (3) Testing trial 
     The mouse was put in the light room at the time of 24 hours after the acquisition trial, and then the guillotine door was opened. The time, which was taken for the limbs of the mouse to enter into the dark room, was measured up to 300 seconds as a scale of the reaction latency and the number of mice which did not enter into the dark room during testing trial, i.e. showing latency longer than 300 seconds, was counted. 
     (4) Preparation for mice with memory defect induced by electroconvulsive shocks 
     Electroconvulsive shock (30 mA, 0.5 second) was applied to the mouse at its ears immediately after the acquisition trial, which caused tetany on the mouse. The mice, which survived after the righting reflex had disappeared, were subjected to the testing trial 24 hours later. 
     (5) Drug administration 
     The test compound was dissolved in distilled water, and the solution was orally administered, in a dose shown in Table 1 to each group consisting of 10 heads at the time of one hour before the testing trial. 
     (6) Amnestic syndrome 
     The testing trial (3) was conducted at one hour after the test compound administration, and the reaction latency was examined for each test mouse. The obtained results are shown in Table 1, and Amnestic syndrome rate (%) is expressed as follows: ##EQU1## 
     
                                           TABLE 1__________________________________________________________________________                   Number of mice    Dose of the    showing latency                           Amnestic    test sample             Number of                   longer than 300                           syndromeTest sample    (mg/kg)          ECS             mice  seconds rate (%)__________________________________________________________________________Control        -  10    6       40(Distilled water)Control        +  10    2       80(Distilled water)Test compound    0.3   +  10    4       60    1.0   +  10    3       70    3.0   +  10    7       30    10.0  +  10    9       10__________________________________________________________________________ ECS: Electroconvulsive shock 
    
     TEST EXAMPLE 2 
     Effect of the test samples on the inhibition of conditioned avoidance response induced by reserpine in rats 
     Std-Wistar male rats (8 to 9 week age) weighing of 270 to 300 g were fed under the conditions of 23±2° C., 60±10% R.H. and artificial lighting from 7 AM to 7 PM for a week, and then subjected to the test. 
     The test was carried out by using a shuttle box. The shuttle box used herein was a rectangular box, which was equipped with a buzzer for conditioned stimulus at the upper part and grids of 2 mm in diameter, for non-conditioned stimulus, at intervals of 1 cm on the floor, and divided into two equal sized compartments by a hurdle of 5 cm in height. 
     The schedule for inducing the conditioned avoidance response was controlled by a computer, and all the observed results of avoidance or escape response were recorded automatically. 
     The avoidance condition was carried out as follows: 
     After the conditioned stimulus of the buzzer with sound signal for 5 seconds, the non-conditioned stimulus of the foot shock was given for 5 seconds to rats. Each stimulus was stopped immediately, if the rat jumped over the hurdle to the other compartment during the conditioned or non-conditioned stimulus. The rats were trained for 50 times a day at the intervals of 30 to 40 seconds, then the rats, which showed 80% and more of the conditioned avoidance response, were used for the next experiment. 
     The above-mentioned rats were put on the trials for 25 times. Then the rats were given reserpine (1 mg/kg, intraperitoneally). The rats were tested for 15 times at the time of 18 to 20 hours after the reserpine administration, and then they were divided into several groups (6 mice/group). 
     The test sample was dissolved in distilled water and administered orally to each group at 24 to 26 hours after the reserpine administration. For reference, distilled water as control sample, and amitriptyline and amantadine as test drugs were used. 
     At one hour after the test sample administration, the rats were put on the trials for 25 times and the conditioned avoidance responce was compared between the control group (distilled water administration), the test compound-administered group and the test drug-administered groups. 
     The obtained results are shown in Table 2. 
     
                                           TABLE 2__________________________________________________________________________          Conditioned avoidance response (%)    Dose of the          before admini-                  18 to 20 hours after                            1 hour after    test sample          stration of                  administration                            administration ofTest sample    (mg/kg)          reserpine                  of reserpine                            the test sample__________________________________________________________________________Control        93      1         2(Distilled water)Test compound    10    90      2         82Amitriptyline    10    93      1         1Amitriptyline    40    94      7         0Amantadine    10    94      3         2Amantadine    50    95      3         38__________________________________________________________________________ *reserpine dose: 1 mg/kg 
    
     TEST EXAMPLE 3 
     Effect of the test samples on the depletion of dopamine induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyrolidine (hereinafter referred to as MPTP) in mice whole brain 
     The test sample, wherein dosulepin, amitriptyline, imipramine, desipramine, mianserin, maprotiline, clomipramine and methamphetamine were used as test drugs in Experiment I, amantadine and methamphetamine in Experiment II and also sufoxazine, indeloxazine and methamphetamine in Experiment III, was administered orally to SlC: ddy strain male mice (7 to 10 heads/group) and after 30 minutes, 50 mg/kg of MPTP was injected subcutaneously. Distilled water in Experiment I, II and III, and a 5% Gum Acacia solution in Experiment III were used as control sample. For reference, the drugs shown in the Table 3 are used. 
     After one week, the mice were decapitated. The whole brain was rapidly removd and homogenized in 0.06M perchloric acid with 3,4-dihydroxybenzyl amine as an internal standard. The homogenate was centrifuged and then, dopamine in the supernatant was determined by means of high performance liquid chromatograpy with electrochemical detection. 
     The obtained results are shown in Table 3. 
     
                       TABLE 3______________________________________                 Percentage of the amount of        Dose of  dopamine in the treated group        the test against the amount of dopamine        sample   in the non-treated groupTest sample  (mg/kg)  (%)______________________________________Experiment INon-treatment         100 ± 10Control               71 ± 11Test compound        10        83 ± 12*        30       85 ± 6*Dosulepin    10       70 ± 13        30       77 ± 12Amitriptyline        10       81 ± 15        30       77 ± 15Imipramine   10       80 ± 14        30       73 ± 14Desipramine  10       74 ± 15        30       79 ± 18Mianserin    10       72 ± 16        30       69 ± 8Maprotiline  10       65 ± 17        30       74 ± 17Clomipramine 10       74 ± 13        30       74 ± 14Methamphetamine         3        97 ± 14**Experiment IINon-treatment         100 ± 21Control               88 ± 20Test compound        10       111 ± 8*Amantadine   10       77 ± 21        30       64 ± 16Methamphetamine         3       102 ± 21*Experiment IIINon-treatment         100 ± 9Control               67 ± 12Control               72 ± 16(5% of Gum Acacia)Sufoxazine   10       76 ± 17        30       68 ± 14Indeloxazine 10       77 ± 17        30       72 ± 19Methamphetamine         3        91 ± 20**______________________________________ *P &lt; 0.05 **P &lt; 0.01 
    
     TEST EXAMPLE 4 
     Effect of the test samples on the re-uptake of  3  H-dopamine in vitro 
     P 2  fraction was prepared from the whole brain of Std: Wistar strain male rat. For reference, amitriptyline was used in Experiment I and dosulepin, imipramine and maprotiline were used in Experiment II.  3  H-dopamine was added in the synaptosome suspension which had been prepared from the P 2  fraction. The obtained mixture was incubated at 37° C. for 20 minutes and then subjected to the suction filtration with Whatman GF/B filter paper. 
     The obtained filter paper was put in a vial containing 10 ml of toluene type scintillator and its radioactivity was measured by means of liquid scintillation counter. The amount of the specific re-uptake of  3  H-dopamine was obtained by subtracting the amount of re-uptake at 0° C. as blank. 
     The obtained results are shown in Table 4. 
     
                       TABLE 4______________________________________Test sample   Number of mice                     IC50 (μM)______________________________________Experiment ITest compound 6           2.0Amitriptyline 6           7.7Experiment IIAmitriptyline 6           8.2Dosulepin     6           9.6Imipramine    6           15.0Maprotiline   6           13.0______________________________________ 
    
     TEST EXAMPLE 5 
     Effect of the test samples on the depletion of norepinephrine induced by 6-hydroxydopamine in rat heart. 
     The test sample was administered orally to Std: Wistar male rats and after 30 minutes, 6-hydroxydopamine (20 mg/kg) was injected intraperitoneally. 
     At 16 hours after injection of 6-hydroxydopamine, the rats were killed. The whole heart was rapidly removed and homogenized in 0.05M perchloric acid with isoproterenol (10 mg/ml) as an internal standard. The homogenate was centrifuged and then the amount of norepinephrine in the supernatant was determined by means of high performance liquid chromatography with electrochemical detection. 
     Desipramine was used as the reference drug and distilled water was used as control sample. 
     The obtained results are shown in Table 5. 
     
                       TABLE 5______________________________________         Dose of the Amount of         test sample NorepinephrineTest sample   (mg/kg)     (ng/g)______________________________________Non-treatment             425 ± 49Control                    20 ± 4Test compound 0.625       169 ± 34**         1.25        247 ± 49**         2.5         306 ± 27**Desipramine   0.625        35 ± 4         1.25         74 ± 26         2.5         211 ± 79**______________________________________ **p &lt; 0.01 
    
     TEST EXAMPLE 6 
     Effect of the test samples on the depletion of serotonin (hereinafter referred to as &#34;5-HT&#34;) induced by p-chloroamphetamine 
     The test sample was administered orally to SlC:ddy made mice and after 60 minutes, p-chloroamphetamine (10 mg/kg) was injected intraperitoneally. 
     At 6 hours later, the mice were decapitated. The whole brain was rapidly removed and homogenized in 0.06M perchloric acid with N-methylserotonin (10 μg/ml) as an internal standard. The homogenate was centrifuged and then the amount of 5-HT in the supernatant was determined by high performance liquid chromatography with electrochemical detection. 
     Amitriptyline was used as the reference drug and distilled water was used as control sample. 
     The obtained results are shown in Table 6. 
     
                       TABLE 6______________________________________                 Percentages of the amount                 of 5-HT in the treated group      Dose of the                 against the amount of 5-HT      test sample                 in the non-treated groupTest sample      (mg/kg)    (%)______________________________________Non-treatment         100 ± 10Control               48 ± 6Test compound       3          64 ± 8**      10          103 ± 10**Amitriptyline      10         50 ± 4      30           56 ± 10**      90          92 ± 8**______________________________________ **p &lt; 0.01 
    
     TEST EXAMPLE 7 
     Effect of the test samples on circling behavior in rats with unilateral substantia nigra lesions 
     Std: Wistar male rats (8 heads/group) were used. The rat with unilateral substantia nigra lesions was made by injecting 8 μg/4 μl of 6-hydroxydopamine to the right side of substantia nigra. 
     The test sample was administered orally to the rat. At 2 hours later, the number of circling behavior per 10 minutes was counted. 
     Amantadine was used as the reference drug and distilled water was used as control sample. 
     The obtained results are shown in Table 7. 
     
                       TABLE 7______________________________________       Dose of the   Number of       test sample   circling behaviorTest sample (mg/kg)       per 10 min.______________________________________Control                   0.1 ± 0.4Test compound        3            3.0 ± 2.9**       10            5.1 ± 4.4**Amantadine  50            0.4 ± 0.7______________________________________ **p &lt; 0.01 
    
     TEST EXAMPLE 8 
     Effect of the test samples on the sleeping time induced by thiopental 
     The test sample was administered orally to Std: Wistar male rats, and at 60 minutes later, sodium thiopental (40 mg/kg) was injected intravenously. 
     The duration of sleeping time was determined as the time period between the injection of thiopental and return of the righting reflex. 
     Distilled water was used as control sample. 
     The obtained results are shown in Table 8. 
     
                       TABLE 8______________________________________          Dose     Sleeping timeTest sample    (mg/kg)  (sec)______________________________________Control                 500.8 ± 12.0Test compound  10       345.6 ± 82.2**          30       338.5 ± 43.7**______________________________________ **p &lt; 0.01 
    
     TEST EXAMPLE 9 
     Effect of the test samples on the sponteneous movement of mice 
     The test sample was administered orally to SlC:ddy male mice. Immediately after, the amount of movement activity of the test mice was measured for 16 hours, at the time of 1, 2, 4, 8 and 16 hours respectively after the oral administration, by means of spontaneous movement measuring system (displacement measuring type). 
     Methamphetamine was used as the reference drug and distilled water was used as control sample. 
     The obtained results are shown in FIG. 1, columns and bars represent the mean±S.D. and statistical significance was evaluated by the multiple comparison test of Dunnet&#39;s type. 
     TEST EXAMPLE 10 
     Acute toxicity 
     SlC:ddy male mice (10 heads/group) were used. 
     After the oral administration of the test smaple, desipramine was used as the test drug, to the mice, the number of the dead mice was counted at 0.5, 1, 2, 4, 18 and 24 hours respectively after the oral administration. 
     The obtained results are shown in Table 9. 
     
                       TABLE 9______________________________________    Dose of the             Number of dead mice per 10 mice    test sample             Time (hr)Test sample      (mg/kg)    0.5   1    2    4    18  24______________________________________Test compound      200         0    1    1    1     2   2      800         4    5    5    6     9   9Desipramine      200         0    0    0    0     0   0      800        10    10   10   10   10  10______________________________________ 
    
     The cerebral function improvers of the present invention containing the test compound as an active ingredient were prepared according to the following Formulation Examples. 
     FORMULATION EXAMPLE 1 
     (Tablets) 
     The tablets (150 mg/one tablet) were prepared according to the prescription as follows: 
     
         ______________________________________Component         Content (mg)______________________________________Test compound     10Corn starch       134Hydroxypropylcellulose             4Magnesium stearate             2______________________________________ 
    
     FORMULATION EXAMPLE 2 
     (Capsules) 
     The capsules (No. 5) were produced by filled with the 100 mg of base materials, which were prepared according the following prescription. 
     
         ______________________________________Component        Content (mg)______________________________________Test compound    10Lactose          50Corn starch      30Crystalline cellulose             8Magnesium stearate             2______________________________________ 
    
     FORMULATION EXAMPLE 3 
     (Injections) 
     The injections were prepared by dissolving 10  mg of the test compound in 1 ml of physiological salt solution, followed by adjusting the pH of the obtained solution to 7.4. 
     In addition to the ingredients or components used in the Examples, other ingredients or components can be used in the Examples as set forth in the specification to obtain substantially the same results.