Effects of chlorpromazine on phosphatidylinositol turnover following thrombin stimulation of human platelets.

Thrombin stimulation of human platelets is known to result in phosphatidylinositol turnover (PI response), the activation of protein kinase C (C-kinase), and the release of arachidonic acid (AA). The authors studied the effects of chlorpromazine (CPZ) on these responses. At a concentration of 100 microM, CPZ inhibited the phosphorylation of 40,000-dalton protein through C-kinase activation. CPZ failed to inhibit initial transient synthesis of 1,2-diacylglycerol (1,2-DAG) through the PI response, although it slowed the concurrent decreasing process. CPZ inhibited promotion of compensatory synthesis of phosphatidylinositol 4,5-bisphosphate (PIP2), and also inhibited the synthesis of phosphatidic acid (PA). These results suggest that phosphatidylinositol 4-monophosphate kinase and diacylglycerol kinase (DAG-kinase) may be inhibited by CPZ. CPZ also intensified the accumulation of inositol phosphates caused by the PI response, indicating possible inhibition of the phosphatases that metabolize these phosphates. Thus, CPZ partially inhibited the PI response. However, it appears likely that the inhibition of C-kinase activity by CPZ was not due to inhibition of 1,2-DAG production nor to direct inhibition of phospholipase C. CPZ also inhibited AA release. This action might be partially a result of the inhibitory effect of CPZ on PA production.

Pharmacokinetic study of iminodibenzyl antipsychotic drugs, clocapramine and Y-516 in dog and man.

The pharmacokinetic properties of the iminodibenzyl antipsychotic drugs clocapramine (CCP, 3-chloro-5-[3-(4-carbamoyl-4-piperidino piperidino) propyl]-10, 11-dihydro-5H-dibenzo[b, f]azepine) and Y-516 (3-chloro-5-[3-(2-oxo-1, 2, 3, 5, 6, 7, 8, 8a-octahydroimidazo [1,2-a] pyridine-3-spiro-4'-piperidino) propyl]-10, 11-dihydro-5H-dibenzo[b, f]azepine) were investigated in dog and man. Dogs were administered CCP and Y-516 intravenously, intraperitoneally, and orally, and the concentrations of the parent drugs and their metabolites in the plasma and urine were determined. Half-life (t1/2) was approximately the same by all three administration routes, being approximately 5 h for CCP and 3 h for Y-516. Bioavailability following oral administration was 0.16 +/- 0.01 (mean +/- SD, n = 3) for CCP and 0.29 +/- 0.07 for Y-516. The fractions of dose absorbed following oral administration were 0.43 +/- 0.07 and 0.79 +/- 0.24, and the fractions of dose metabolized in the liver due to the first-pass effect were 0.63 +/- 0.05 and 0.63 +/- 0.04 for CCP and Y-516, respectively. Y-516 was detected in the plasma after intraperitoneal and oral administration of CCP. The ratio of the AUC of Y-516 to that of CCP was 0.06 following intraperitoneal administration and 0.40 following oral administration. This indicated that while the metabolism of CCP into Y-516 may occur partly in the liver due to the first-pass effect, it occurs mostly within the gastrointestinal tract itself or its mucosa.(ABSTRACT TRUNCATED AT 250 WORDS)

A sporadic case of benign myoclonus epilepsy of adult onset: its clinical aspects and electroencephalographic, polygraphic study.

A sporadic case of myoclonus epilepsy of adult onset with a benign course is presented. Its clinical implications were discussed symptomatologically and nosologically. EEG findings consisted of the slowing of basic activity, characteristic polyspike and wave discharges or other paroxysmal patterns and photomyoclonic response (PMR). The PMR was well evoked by flashes of 6-21 Hz and of yellow or red color. Clinical similarities of this case to those of hereditary myoclonus epilepsy without progressive dementia and cerebellar ataxia, and pathognomonic characteristics of electrophysiological findings indicated that the myoclonic epilepsy syndrome might share basic properties, which are state-dependent, but independent of underlying neuropathology or heredity. During sleep, paroxysmal discharges with spike(s) significantly decreased in slow-wave sleep and almost recovered in REM sleep. This finding suggests that the brain stem may be responsible for the epileptogeneity in this case.

Different effects of centrally acting drugs on rabbit platelet aggregation: with special reference to selective inhibitory effects of antipsychotics and antidepressants.

Twenty-four drugs, consisting of antipsychotics, tricyclic antidepressants, other centrally acting drugs, and related compounds, were studied for their effects on aggregation of rabbit platelets. Phenothiazine neuroleptics, haloperidol, sultopride, tricyclic antidepressants, sulpiride, atropine, and propranolol showed a selective inhibitory effect on the collagen-induced aggregation, but not on aggregations induced by arachidonic acid (AA) or adenosine diphosphate (ADP). These drugs are thought to inhibit the liberation of AA from phospholipids in platelet membranes, suggesting that they might inhibit phospholipases. Mepyramine, promethazine, phentolamine, and clozapine inhibited the aggregations evoked by collagen and AA, but failed to inhibit the ADP-induced aggregation. These drugs might inhibit the generation of prostaglandin endoperoxides or thromboxanes. Phenobarbital, phenytoin, procaine, lidocaine, flurazepam, trihexyphenydil, and lithium carbonate did not inhibit any kind of aggregation at the concentrations used. The clinical and pharmacological significance of these findings is discussed; it seems that the inhibitory effects of antipsychotics and antidepressants on platelet aggregation are closely related to the specific clinical and psychotropic effects of these drugs, but not to other actions.