title: Cardiovascular activity of the crude alkaloidal fraction from Tabernaemontana pandacaqui in the rat.
abstract: The effects of a crude alkaloidal (CA) fraction from the stem of Tabernaemontana pandacaqui Poir. on the blood pressure and heart rate were investigated in conscious as well as anesthetized rats. The CA fraction exerted a hypotensive activity in both experimental models. In pentobarbital anesthetized rats, an intravenous administration of the CA fraction caused two consecutive hypotensive and bradycardiac responses. In order to investigate the mechanism of the responses, the effect of the CA fraction on the blood pressure and the heart rate was tested in various experimental animals such as pithed rats, reserpinized rats under pentobarbital anesthesia and atropine- or chlorpheniramine-treated rats under pentobarbital anesthesia. The results obtained suggest that the hypotensive and bradycardiac responses of the first phase might involve cholinergic and central mechanisms, whereas those of the second phase involve mechanisms which are mediated by central, biogenic amines, acetylcholine and histamine.
authors.affiliation: Department of Pharmacology, Faculty of Medicine, Chiang Mai University, Thailand.
authors.forename: T
authors.initials: T
authors.lastname: Taesotikul
authors.forename: A
authors.initials: A
authors.lastname: Panthong
authors.forename: D
authors.initials: D
authors.lastname: Kanjanapothi
authors.forename: R
authors.initials: R
authors.lastname: Verpoorte
authors.forename: J J
authors.initials: JJ
authors.lastname: Scheffer
mesh_terms: D000759:Adjuvants, Anesthesia; D000470:Alkaloids / Q000494:pharmacology*; D000818:Animals; D000959:Antihypertensive Agents / Q000494:pharmacology*; D001794:Blood Pressure / Q000187:drug effects; D002744:Chlorpheniramine / Q000494:pharmacology; D006339:Heart Rate / Q000187:drug effects; D010424:Pentobarbital; D010936:Plant Extracts / Q000494:pharmacology*; D010946:Plants, Medicinal / Q000737:chemistry*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012110:Reserpine / Q000494:pharmacology
chemical_list: D000759:Adjuvants, Anesthesia; D000470:Alkaloids; D000959:Antihypertensive Agents; D010936:Plant Extracts; D002744:Chlorpheniramine; D012110:Reserpine; D010424:Pentobarbital