Inhibitory effects of aqueous extract of Hibiscus sabdariffa on contractility of the rat bladder and uterus.
We examined an aqueous extract of Hibiscus sabdariffa calyces extracts (HSE) by close-arterial injection on micturition thresholds (MTs) and on uterine contractions (rate and amplitude). Five doses of HSE were examined (1, 5, 10, 50, and 100 mg/kg) in 3 groups of rats: controls, after bladder inflammation, and after bilateral hypogastric neurectomy. In some rats, uterine contractions were induced by injection of oxytocin (OT) and the effect of HSE was compared with that of nifedipine. HSE increased MTs in a dose-dependent manner in all groups. Neither atropine (0.1 mg/kg) nor propranolol (0.4 mg/kg) had significant effects on cystometric parameters. They also did not affect the responses obtained by HSE on cystometric parameters. As with bladder response, HSE inhibited both the rate and amplitude of uterine contractions in all groups in a dose-dependent manner. The uterine response to HSE was not affected by administration of either atropine or propranolol. A slight, but significant, reduction of contraction amplitude by HSE in the OT precontracted uteri was only noted at a dose of 500 mg/kg. Nifedipine was more potent than HSE in reducing uterine contraction amplitude. The present work documents inhibition by HSE of the rat bladder and uterine contractility in a dose-dependent manner via a mechanism unrelated to local or remote autonomic receptors or calcium channels. However, further investigation is needed to establish the exact mechanism of action.
Department of Clinical Pharmacology, Mansoura Faculty of Medicine, Mansoura University, DK 35516 Mansoura, Egypt. foudaamm@mans.edu.sg
Abdel-Motaal M
AM
Fouda
Mohamad-Hesham Y
MH
Daba
Gamal M
GM
Dahab
D000818:Animals; D003556:Cystitis / Q000503:physiopathology*; D004305:Dose-Response Relationship, Drug; D005260:Female; D031584:Hibiscus / Q000737:chemistry*; D007001:Hypogastric Plexus; D007269:Injections, Intra-Arterial; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects / Q000294:innervation / Q000503:physiopathology; D010936:Plant Extracts / Q000302:isolation & purification / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D013562:Sympathectomy; D001743:Urinary Bladder / Q000187:drug effects / Q000294:innervation / Q000503:physiopathology*; D014554:Urination / Q000187:drug effects; D014590:Uterine Contraction / Q000187:drug effects*; D014599:Uterus / Q000187:drug effects / Q000294:innervation
D010936:Plant Extracts