Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0011570 (depression)
 172,036 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Pyrithiamine (50 mg/kg), a thiamine antagonist, decreased the muscle twitches of the rat masseter muscle at stimulation frequencies above 1 Hz 40--80 min after an i.v. injection. The post-tetanic potentiation (PTP) induced by nerve stimulation of the masseter muscle was abolished by pyrithiamine. Administration of thiamine restored the muscle twitches at stimulation frequencies above 1 Hz and the PTP. The muscle twitches elicited by direct muscle stimulation were not affected by pyrithiamine treatment. The abolishment of the PTP was accompanied by a decrease in thiamine and thiamine-diphosphate. The pyruvate level in the blood was unchanged after pyrithiamine treatment. Oxythiamine, on the other hand, had no effect on the PTP but increased the pyruvate level in the blood. Fern extract which contains thiaminase I also abolished the PTP--an effect reversible by the addition of thiamine. The frequency-induced depression of the muscle twitches induced by pyrithiamine was similar to the effect of low doses of d-tubocurarine (8 microgram/kg). The results support the hypothesis that thiamine may play a role in neuromuscular transmission.
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PMID:Possible role of thiamine in neuromuscular transmission. 21 39

Oxythiamine B1-hypovitaminosis in adrenalectomized male rats is not accompanied by acute thymus involution. This is not so much related to hypocorticoidism per se, as to a decrease in metabolic potencies of the antivitamin, particularly to a negligible depression of thymocyte tolerance to hydrocortisone. Sex differences in morphological parameters of thymus lymphopoiesis have been found after adrenalectomy.
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PMID:[Corticosteroid mechanism as a leading element of the thymotropic effect of oxythiamine in the rat]. 715 Jul 37

The electrogenic tissue of Torpedo was found to phosphorylate in vitro external [14C]thiamine by a saturable process. The rate of this metabolisaton was increased when acetate, an efficient precursor of acetylcholine (ACh) synthesis in this tissue, was added to the incubation medium, thus increasing the turnover of ACh. Nerve stimulation did not release significant amounts of the previously accumulated [14C]thiamine. Exogenous thiamine modified the size of the electroplaque potential (e.p.p.). At concentrations higher than 10(-3)M the nerve-electroplaque transmission was depressed after a transient increase of the e.p.p. Such a depression was due to a strong decrease of the ACh release. At concentrations equal to or lower than 10(-3)M, thiamine affected transmission in a rather complex fashion. ACh release was decreased or increased depending on concentration, time of application, and mode of stimulation. Oxythiamine, a structural antimetabolite of thiamine, affected the transmission in a very characteristic manner at 10(-5)M and higher concentrations. The amplitude of the e.p.p. was increased and, more strikingly, its duration was prolonged. These changes were not due to an inhibition of cholinesterase activity but to an enhancement of the evoked release of ACh either on single-impulse or repetitive stimulation. Another antimetabolite, pyrithiamine, had no effect on the transmission nor on ACh release. From this and our previous work, it is proposed that thiamine is involved, directly or indirectly, in the process of ACh release. The possible mechanisms of this involvement are discussed.
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PMID:Thiamine and cholinergic transmission in the electric organ of Torpedo. II. Effects of exogenous thiamine and analogues on acetylcholine release. 744 Dec 50