Effects of amantadine on modification of dopamine dependent behaviours by molindone.

Amantadine, a dopamine agonist is reported to act by releasing dopamine from the dopaminergic nerve terminals as an anti-Parkinsonian drug. In the present behavioural study in the rat, molindone-induced catalepsy and ptosis, which are dopamine dependent-behaviors are reversed by amantadine. Amantadine has also revered molindone-induced inhibition of traction response in mice. Our study indicates that amantadine, like other DA agonists, e.g. amphetamine and apomorphine can antagonize or even reverse the neuroleptic induced dopaminergic behaviors.

Effects of yohimbine on dopamine dependent behaviours in rats and mice.

In the present study we have investigated the effect of yohimbine on dopamine-dependent behaviours in rats and mice. Yohimbine (1.25 to 10 mg/kg, ip) failed to block the conditioned avoidance response in rats, to inhibit the traction response in mice and to induce catalepsy in rats and mice. Pretreatment with yohimbine (1.25 to 10 mg/kg, ip) had no significant effect on apomorphine stereotypy in rats and apomorphine induced cage climbing behaviour in mice. However, pretreatment with yohimbine (1.25 to 10 mg/kg. ip) significantly increased the intensity of methamphetamine stereotypy and antagonised haloperidol catalepsy in rats. Our findings indicate that yohimbine does not possess postsynaptic striatal and mesolimbic D-2 dopamine receptor blocking activity.

Effect of inhibition of lens membrane Na+-K+ ATPase by ouabain pre-treatment--an in vitro study.

The precise factors responsible for the cataract formation are not known. The role of Na+-K+-ATPase in maintaining ionic concentration of lens and lens membrane permeability and its involvement in the formation of cataracts has been of recent interest. Thus the present study was undertaken to study the effect of pre-treatment with Ouabain, a known Na-K-ATPase inhibitor, on the intra-lenticular ionic concentration and the rule of lens membrane permeability in cataractogenesis. Fresh goat lenses were used for the experimental work. Isolated lens culture technique was used. The electrolytes were estimated before and 24 hours after Ouabain pre-treatment. The electrolyte pattern showed significant changes after pre-treatment with Ouabain. Lens sodium ion concentration increased significantly with a concommitant decrease in potassium ion concentration. Intra-lenticular chloride concentration also showed a significant increase as compared to control. Calcium and magnesium ion concentrations also showed slight increase after the inhibition of Na+-K+-ATPase system by Ouabain.

Head-twitch response induced by ergometrine in mice: behavioural evidence for direct stimulation of central 5-hydroxytryptamine receptors by ergometrine.

Ergometrine (2.5-80 mg/kg IP) induced head twitches in mice. Pretreatment with cyproheptadine (1.5 and 3 mg/kg), methysergide (5 and 10 mg/kg) and (-)-propranolol (2.5 and 5 mg/kg) significantly decreased the number of head twitches induced by ergometrine. Pretreatment with p-chlorophenylalanine (100 mg/kg/day X 4 days) and clomipramine (5 and 10 mg/kg) significantly decreased the number of head twitches induced by fenfluramine (10 mg/kg) and p-chloramphetamine (5 mg/kg) but had no significant effect on the number of head twitches induced by ergometrine. The results indicate that ergometrine induces head twitches in mice by directly stimulating central 5-hydroxytryptamine receptors.

Antagonism of bromocriptine-induced cage climbing behaviour in mice by the selective D-2 dopamine receptor antagonists, metoclopramide and molindone.

Bromocriptine (5-30 mg/kg, ip), 2 hr after administration, induced cage climbing behaviour in mice. Pretreatment with haloperidol, an antagonist of both D-1 and D-2 dopamine receptors, metoclopramide and molindone, the selective D-2 dopamine receptor antagonists, effectively antagonised bromocriptine-induced climbing behaviour. The results indicate that bromocriptine most probably induces climbing behaviour in mice by stimulating the postsynaptic striatal D-2 dopamine receptors.

Effect of ergometrine on methamphetamine and apomorphine stereotypy in the guinea-pig.

Pretreatment with the DAi receptor antagonist ergometrine (10, 20 mg kg-1 i.p.) significantly potentiated methamphetamine stereotypy and facilitated the induction of biting, gnawing or licking behaviour by amantadine. However, ergometrine (5-20 mg kg-1) did not significantly influence the stereotyped behaviour induced by the DAe receptor agonist apomorphine. The results suggest that the DAi antagonist ergometrine is effective in modifying the behaviours induced by methamphetamine and amantadine, agents which through released DA simultaneously activate both DAe and DAi receptors, but fails to modify the stereotyped behaviour induced by apomorphine which specifically activates only DAe receptors. However, the possibility that ergometrine might have potentiated methamphetamine stereotypy and facilitated the induction of biting, gnawing or licking behaviour by amantadine through modulation of the activity of the central noradrenergic and 5-hydroxytryptaminergic systems, which are reported to influence DA-mediated behaviours, also needs to be considered.

Correlation between serum choline esterase and serum albumin in leprosy.

The clinical material included 255 cases of leprosy consisting of Tuberculoid leprosy (74), Lepromatous leprosy (116), Lepromatous leprosy with lepra reaction. Liver biopsy could be performed on 50 cases of Lepromatous leprosy. Specific granulomatous changes and parenchymal cell damage were the significant findings. Serum choline esterase and serum albumin are synthesized in liver. Serum Choline esterase levels in the present study decreased abruptly with exacerbation of the disease but the serum albumin levels declined gradually and slowly. Possible hypothesis to explain the correlation and uneven fall in activity is discussed at the cellular level.

L.D.H. isoenzymes sub-unit ratio in leprosy and the effect of clofazimine treatment on L.D.H. isoenzymes sub-unit.

The clinical material for our studies of serum total LDH activity and LDH isoenzymes in leprosy included 255 patients consisting of Tuberculoid (74), Lepromatous leprosy (116), and Lepromatous leprosy with lepra reaction (65). 20 patients with suspected DDS resistance and repeated attacks of lepra reactions were selected for Clofazimine studies. All leprosy patients exhibited higher total LDH activity as compared to normals. M/H ratio was significantly increased in patients of Lepromatous leprosy and correlated closely with the clinical severity and advancement of disease. Tuberculoid leprosy patients showed values close to normals. Hence M/H ratio could demarcate two polar types of leprosy i.e. Tuberculoid and Lepromatous leprosy. Clofazimine treatment over a period of one year in patients with suspected DDS resistance and repeated attacks of lepra reaction decreased total LDH activity and M/H ratio considerably. Fall in M/H ratio during Clofazimine treatment could be attributed to the clearance of 'M' subunits by the drug due to removal of blockade of R.E.S. system produced by lepra bacilli.

Antagonism of apomorphine-induced cage climbing behaviour and methamphetamine stereotypy by fenfluramine in mice.

Pretreatment with fenfluramine (5 and 10 mg/kg, ip) in doses which induced head twitches was found to antagonize apomorphine-induced cage climbing behaviour and methamphetamine stereotypy in mice. Since fenfluramine (5 and 10 mg/kg) did not induce catalepsy it indicates that fenfluramine lacks postsynaptic striatal and mesolimbic dopamine receptor blocking activity and it is possible that the fenfluramine-induced enhancement of central 5-hydroxytryptamine neuronal transmission may be responsible for its antagonistic effect on apomorphine-induced climbing behaviour and methamphetamine stereotypy.

Psychopharmacological investigation of the monoamine oxidase inhibitory activity of molindone, a dihydroindolone neuroleptic.

24 h pretreatment with molindone enhanced the behavioural effects of L-dopa and 5-HTP, precursors of biogenic amines (catecholamines and 5-HT respectively) preferentially deaminated by MAO-A, confirming that a metabolite of molindone inhibits MAO-A. 24 h pretreatment with molindone enhanced the behavioural effects of tryptamine and antagonized reserpine-induced ptosis, and in molindone-pretreated rats L-tryptophan induced behavioural effects, probably because of the MAO-A inhibitory activity exerted by a metabolite of molindone. Since 24 h pretreatment with molindone, unlike 30 min pretreatment with clomipramine, failed to antagonize fenfluramine and p-chloramphetamine-induced behavioural syndromes, it suggests that molindone and/or its metabolites most probably do not exert 5-HT neuronal uptake blocking activity and the potentiation of 5-HTP-induced behavioural syndrome is due to a metabolite's MAO-A inhibitory activity. As 2 h pretreatment with molindone induced catalepsy and antagonized apomorphine-induced climbing behaviour in mice and stereotypy in rats, while 24 h pretreatment failed to induce catalepsy and to antagonize apomorphine-induced behaviour, it appears that, at 24 h, the tissue levels of molindone are inadequate to block postsynaptic striatal and mesolimbic DA receptors and that, though a metabolite of molindone is biologically active so far as inhibition of MAO-A is concerned, the metabolites are devoid of neuroleptic activity. Further, since 2 h pretreatment with molindone failed to enhance the behavioural effects of L-dopa, it suggests that at 2 h the degree of MAO-A inhibition induced by molindone and/or the metabolite is not sufficient to counteract the neuroleptic activity of the parent compound.

Thalidomide in lepra reaction (ENL) in lepromatous leprosy patients.

Six male bacteriologically highly positive patients of lepromatous leprosy with ENL reaction not adequately controlled by conventional antireaction drugs were put on thalidomide 400 mg per day in four divided doses. Reaction was controlled between 13th to 18th day of therapy. There was no change in the bacteriological status. Liver functions, renal functions and hemogram were normal before therapy and remained unaltered at the end of treatment. Apart from fatigue, drowsiness and occassional constipation, thalidomide had no adverse effect. Control of ENL reaction by thalidomide in these patients is probably due to its immunosuppressive effect, more likely by its stablising action on lysosomes.

Once monthly rifampicin (1200 mg) plus daily dapsone (100 mg) and clofazimine (100 mg) in the initial treatment of lepromatous leprosy.

The therapeutic effect of rifampicin 1200 mg once monthly and 100 mg clofazimine daily for the first six months of treatment was evaluated in 30 patients of bacteriologically positive lepromatous leprosy patients. Moderate to marked clinical improvement was seen in all the patients and a very rapid bacteriological regression as indicated by the decrease in bacteriological and morphological indices of the skin within one week. Seven patients become MI negative at one month and three months and 13 at the end of nine months. Two patients became MI and BI negative at the end of six months and six at the end of nine months. These observations clearly establish the high therapeutic efficacy and practicability of the three drug regimen. Once monthly rifampicin is highly effective and well tolerated, and has many advantages like low cost, better patient compliance and reliability of the treatment. Addition of clofazimine to rifampicin and dapsone prevents the emergence of E.N.L. reactions which were seen during treatment with once monthly rifampicin and daily dapsone. This regimen is thus ideal for initial, intensive treatment of lepromatous leprosy and may help in preventing the spread of the disease and development of dapsone resistance.

Effects of naloxone on methamphetamine and apomorphine stereotypy and on haloperidol catalepsy in rats.

Pretreatment with the opiate antagonist naloxone, at 1.25-5 mg/kg, increased the intensity of methamphetamine stereotypy, had no effect (over a range of 0.3125-5 mg/kg) on apomorphine stereotypy, and antagonized haloperidol catalepsy in rats at 1.25-5 mg/kg. It is suggested that naloxone, by blocking the opiate receptors located on the nigro-striatal and mesolimbic dopamine (DA) nerve terminals, releases the DA systems from endogenous inhibition, presumably caused by endogenous opiate systems, and thereby potentiates methamphetamine stereotypy and antagonizes haloperidol catalepsy. However, the possibility that naloxone might have affected methamphetamine stereotypy and haloperidol catalepsy by modulating the activity of the central noradrenergic and GABAergic systems, which are reported to influence dopaminergically mediated behaviours, also needs to be considered.

The effect of clofazimine on liver function tests in lepra reaction (ENL).

Twenty patients with suspected DDS resistance and repeated attacks of lepra reactions were selected for the study. Clofazimine was administered in different doses over a period of 12 months. Elevated levels of transaminases and Alkaline phosphatase prior therapy attained values to near normalcy. Progressive fall in serum Bilirubin and Proteins with normal A/G ratio at the end of therapy was also observed. Clofazimine by its anti-inflammatory and antibacterial action could inhibit the process of liver damage and happened to have minimal deleterious effect on liver by studying the liver function tests.