Methyldopa potentiated hypnosis due to hexobarbitone in mice, as did reserpine, chlorpromazine and 5-hydroxytryptamine. Methyldopa antagonized the increase by reserpine of sleep due to hexobarbitone, but enhanced the potentiation by chlorpromazine and 5-hydroxytryptamine of hypnosis due to hexobarbitone. The sedative effect of reserpine in mice and the emetic effect in pigeons were also antagonized by methyldopa. However, the effects of reserpine on convulsions due to leptazol and in causing ptosis were not antagonized by methyldopa.
Seven structurally-related compounds consisting of three antidepressant drugs (imipramine, desmethylimipramine and amitriptyline), three tranquillizing agents (promazine, chlorpromazine and chlorprothixene) and a hybrid, desmethylpromazine, have been examined in a series of tests involving autonomic functions and antagonism of reserpine.
In rats, propranolol potentiated alcohol and pentobarbitone hypnosis, but not barbital sleeping time, indicating enzyme inhibition as a possible mechanism of potentiation. Propranolol showed anticonvulsant effect on normal and reserpine treated rats by MES test, but showed dose related lowering of MET. Probable mechanisms are discussed.
The known sesquiterpene valeranone (= Yatamanson) was isolated from the subterranian parts of Nardostachys yatamansi (DC). It was pharmacologically investigated in animal experiments of sedative, tranquilizing and antihypertensive properties. In some experiments, typical for tranquilizers, certain activities could be demonstrated such as the prolongation of barbiturate hypnosis, the impairment of rotarod performance, an anticonvulsive activity on electric shock and potentiation of the body-temperature lowering activity of reserpine.
The pharmacological effects of the new platelet aggregation inhibitor cilostazol (6-(4-(1-cyclohexyl-1 H-tetrazol-5-yl)butoxy]-3,4-dihydro-2(1H)-quinolinone, OPC-13013) on the central nervous system were studied. Cilostazol had little effect on the general behavior of mice up to a dose of 1000 mg/kg p.o. and caused disappearance of pinna reflex, alertness and startle response and slight ptosis in only one of 6 rats at a dose of 1000 mg/kg p.o.
IDPH-791, when injected (ip) to mice potentiated the pentobarbitone sleeping time in a dose dependent manner. Involvement of neurotransmitters and receptors in this effect was studied using various receptor blockers, enzyme inhibitors, agonist and an amine depletor. Pretreatment with high dose of yohimbine (0.5 mg/kg), haloperidol, cyproheptadine, atropine and a combination of atropine and yohimbine significantly reversed the activity.
Reserpine, an alkaloid from Rauwolfia serpentina, was widely used for its antihypertensive action. However, its use has been reduced because of its sedative and extra pyramidal symptoms. In the present investigation, reserpine methiodide (RMI), a quaternary analogue of reserpine, was synthesized and pharmacologically evaluated in rats and mice for its central (barbiturate hypnosis, spontaneous motor activity, body temperature, and avoidance of conditioned response) and peripheral actions (blood pressure) in comparison with reserpine.
European Neuropsychopharmacology: The Journal of the European College of Neuropsychopharmacology
The ?-phenylethylamines are known to act as ligands for the trace amine receptors, a novel family of G-protein-coupled receptors. The trace amines are stored and released along with various neurotransmitter agents such as norepinephrine, serotonin, and dopamine and thus work as neuromodulator or neurotransmitter agents. Trace amines are known to play an important role in the pathophysiology of major depression.