Research communications in chemical pathology and pharmacology
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Res. Commun. Chem. Pathol. Pharmacol. · Oct 1980
Effects of fluoxetine on electrically-induced spinal cord seizures in rats.
The effects of fluoxetine [an inhibitor of 5-hydroxytryptamine (5-HT) reuptake] on electrically-induced spinal cord seizures were determined by monitoring alterations in the total duration of seizure, as well as the durations of tonic flexion and extension. The capacity of fluoxetine to inhibit 5-HT reuptake in the spinal cord was confirmed by measurements of 5-hydroxyindoleacetic acid (5-HIAA) content. ⋯ However, a dose of 20 mg/kg did significantly reduce 5-HIAA content although it did not alter seizure activity. These results further support our earlier suggestion that 5-HT containing neurons in the spinal cord do not modulate electrically-induced seizures.
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Res. Commun. Chem. Pathol. Pharmacol. · Oct 1980
Effects of norepinephrine and 5-hydroxytryptamine reuptake inhibitors on electrically-induced spinal cord seizures in rats.
Nisoxetine and desipramine (inhibitors of norepinephrine reuptake) each exerted a suppressant effect on spinal cord seizures by decreasing the duration of tonic extension. In addition, desipramine increased the duration of tonic flexion and nisoxetine decreased the total duration of seizure. In contrast, citalopram (an inhibitor of 5-hydroxytryptamine reuptake) did not affect any of these seizure components. These observations support the concept that spinal cord noradrenergic, but not 5-hydroxytryptaminergic neurons act as attenuators of convulsive activity.
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Res. Commun. Chem. Pathol. Pharmacol. · Aug 1979
In vitro effect of levamisole on oxygen consumption and survival of platelets.
Levamisole at a concentration of 10(-3)M inhibits the oxygen consumption of resting platelets, the thrombin induced burst and the platelet aggregation induced by ADP. At the concentration of 10(-7)M it exerts still an inhibitory activity of the thrombin induced burst, but it does not inhibit neither the basal oxygen consumption nor the platelet aggregation. ⋯ Levamisole moreover, together with theophylline and glucagon, shows a synergistic inhibiting influence toward the burst of oxygen consumption. Our data suggest that levamisole may act by producing an enzymatic block of cyclo-oxygenase.
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Cocaine plasma concentration-response-time data obtained from the literature were analyzed by pharmacokinetic methods. The plasma concentration-time data yield an elimination half-life of approximately 1 hour and the data suggest that only about 20% of an oral dose of cocaine is absorbed intact into the systemic circulation. ⋯ The rate of decline of response is a function of the apparent first-order elimination rate constant (K) of the drug and the slope of the response-log plasma concentration curve (m). A value for m of 4.2 "high" was calculated from the response-time data which agreed well with a value of 3.9 "high" for m determined from the slope of the response-log plasma concentration curve.
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Isolated chicken bronchus (which had been partially contracted to carbachol) relaxes to isoproterenol and epinephrine but contracts weakly to phenylephrine. Propranolol (a beta-adrenoceptor blocker) antagonizes isoproterenol and reverses epinephrine-induced relaxations to feeble contractions. Phenylephrine-induced bronchoconstrictions and constrictions to epinephrine (in the presence of beta-blockade) were blocked by phentolamine. The results of this study showed the predominance of beta-)inhibitory) adrenoceptors and some alpha-(excitatory) adrenoceptors in the bronchus of the adult domestic fowl.