Pharmacological actions of Heteromorpha trifoliata ("dombwe") on rat isolated muscle preparations.
OBJECTIVE
To investigate the effects of Heteromorpha trifoliata on rat uterine and skeletal muscle.


METHODS
Laboratory based study using experimental animals. Investigating the effects of the plant extract and agonists on isolated muscle preparations.


METHODS
Department of Physiology, University of Zimbabwe.


METHODS
28 Sprague-Dawley rats.


METHODS
Amplitude of contraction of uterine smooth muscle and skeletal muscle.


RESULTS
Experiments were performed on the isolated rat uterus preparation in which strips of myometrium were placed in tissue baths filled with Kreb's solution. The aqueous extract of the root bark of Heteromorpha trifoliata ("dombwe") contracted the rat uterus. The contractions were not antagonised by atropine but were blocked by both cyproheptadine and verapamil. In addition, "dombwe" induced a contracture of the rat diaphragm muscle in the presence of alcuronium.


CONCLUSIONS
The contractile effects on the uterus appear to involve stimulation of 5-HT2 receptors leading to an increase in calcium influx into the smooth muscle cell. Promotion of calcium influx could also explain the effects observed on the skeletal muscle preparation since the contracture induced by "dombwe" occurred in the presence of the nicotinic antagonist, alcuronium. In view of the effects of "dombwe" on other smooth muscle preparations (from previous work) it appears that the pharmacological profile of the crude aqueous extract of the root bark of Heteromorpha trifoliata is complex and suggestive of the presence of more than one active ingredient.
Katerere
D
D
Department of Physiology, University of Zimbabwe, P O Box M P 167, Harare, Zimbabwe.
Parry
O
O
D000443:Alcuronium / Q000494:pharmacology; D000818:Animals; D019661:Apiaceae / Q000502:physiology*; D001285:Atropine / Q000494:pharmacology; D002121:Calcium Channel Blockers / Q000494:pharmacology; D003533:Cyproheptadine / Q000494:pharmacology; D004353:Drug Evaluation, Preclinical; D005260:Female; D066298:In Vitro Techniques; D008297:Male; D016488:Medicine, African Traditional; D018727:Muscarinic Antagonists / Q000494:pharmacology; D009119:Muscle Contraction / Q000187:drug effects*; D018482:Muscle, Skeletal / Q000187:drug effects*; D009215:Myometrium / Q000187:drug effects*; D018733:Nicotinic Antagonists / Q000494:pharmacology; D008517:Phytotherapy / Q000379:methods*; D024301:Plant Bark / Q000502:physiology; D010936:Plant Extracts / Q000819:agonists / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D044348:Receptors, Serotonin, 5-HT2 / Q000187:drug effects; D012702:Serotonin Antagonists / Q000494:pharmacology; D014590:Uterine Contraction / Q000187:drug effects*; D014700:Verapamil / Q000494:pharmacology; D015030:Zimbabwe
D002121:Calcium Channel Blockers; D018727:Muscarinic Antagonists; D018733:Nicotinic Antagonists; D010936:Plant Extracts; D044348:Receptors, Serotonin, 5-HT2; D012702:Serotonin Antagonists; D003533:Cyproheptadine; D001285:Atropine; D014700:Verapamil; D000443:Alcuronium