title: Effect of scorpion toxin from Tityus serrulatus on the contraction of the isolated rat uterus.
abstract: Scorpion toxin T1 from Tityus serrulatus was tested for its effects on the isolated rat uterus preparation. T1 (5 micrograms/ml) caused a contraction of the uterus, which was potentiated by neostigmine (1.64 x 10(-6) M) and abolished by atropine (1.4 x 10(-7) M). After addition of neostigmine to the bath, we noted a higher amplitude of the toxin-induced contractions, and the appearance of repetitive rhythmic contractions. The scorpion toxin-induced contraction was not prevented by previous addition to the bath of hexamethonium or bradykinin, 5-HT and angiotensin II antagonists. The uterine contraction was prevented by previous addition to the bath of either tetrodotoxin (5 x 10(-8) M) or lidocaine (4.2 x 10(-5) M). These data seem to indicate that scorpion toxin-induced rat uterus contractions are due to actions on post-ganglionic autonomic nerve endings, with acetylcholine release and stimulation of muscarinic receptors.
authors.affiliation: Departamento de Ginecologia, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil.
authors.forename: M
authors.initials: M
authors.lastname: Mendonça
authors.forename: M M
authors.initials: MM
authors.lastname: Da Luz
authors.forename: L
authors.initials: L
authors.lastname: Freire-Maia
authors.forename: J R
authors.initials: JR
authors.lastname: Cunha-Melo
mesh_terms: D000109:Acetylcholine / Q000378:metabolism; D000804:Angiotensin II / Q000037:antagonists & inhibitors; D000818:Animals; D001285:Atropine / Q000494:pharmacology; D001920:Bradykinin / Q000037:antagonists & inhibitors; D005591:Chemical Fractionation; D004347:Drug Interactions; D004357:Drug Synergism; D005260:Female; D018738:Hexamethonium / Q000494:pharmacology; D066298:In Vitro Techniques; D008012:Lidocaine / Q000494:pharmacology; D009388:Neostigmine / Q000494:pharmacology; D051381:Rats; D011976:Receptors, Muscarinic; D012604:Scorpion Venoms / Q000378:metabolism / Q000633:toxicity*; D012605:Scorpions; D012702:Serotonin Antagonists / Q000494:pharmacology; D013779:Tetrodotoxin / Q000494:pharmacology; D014118:Toxins, Biological / Q000302:isolation & purification / Q000633:toxicity*; D014590:Uterine Contraction / Q000187:drug effects*
chemical_list: D011976:Receptors, Muscarinic; D012604:Scorpion Venoms; D012702:Serotonin Antagonists; D014118:Toxins, Biological; D000804:Angiotensin II; D009388:Neostigmine; D018738:Hexamethonium; D013779:Tetrodotoxin; D001285:Atropine; D008012:Lidocaine; D000109:Acetylcholine; D001920:Bradykinin