Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0406810 (NAME)
 13,345 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Relatively little data is available on regional differences in both morphological and functional studies of vaginal smooth muscle in the rabbit. Histological and in vitro strip studies were performed upon the vaginal walls of 10-week-old New Zealand White rabbits discriminately according to location (upper, middle or lower) and the type of muscle arrangement (longitudinal or circular). The contraction and relaxation responses of the vaginal smooth muscle were assessed. The upper and middle third of the vagina were histologically characterized by an abundance of smooth muscle, while the lower third was composed of numerous sinusoids scattered among smooth muscle bundles. The peak amplitudes of 60 mM KCl-induced contraction per tissue strip weight were regionally different (upper>middle>lower). Contractile responses induced by adrenergic agonists (epinephrine, norepinephrine, phenylephrine and isopreterenol) showed regional differences, and were mainly of a tonic nature in lower part and strong phasic in middle and upper vagina. Electrical field stimulation induced a prominent relaxation response in the lower third of the vagina precontracted with phenylephrine (5 microM). This relaxation response was partially inhibited by N-omega-nitro-L-arginine methyl ester (NAME, 43.3+/-6.9%, s.e.), a nitric oxide synthase inhibitor, and D-vasoactive intestinal peptide (VIP) (11.3+/-4.4%), a VIP receptor antagonist. The type of muscle arrangement did not affect the results. Our results demonstrated that rabbit vagina has regional difference, not only histologically but also functionally. The contractile response was induced in all regions of the rabbit vagina by sympathetic agonists, while the prominent nerve-mediated relaxation was identified in the lower third portion of the rabbit vagina. The nature of relaxation and contractile function of vagina awaits future investigation.
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PMID:Histological and functional aspects of different regions of the rabbit vagina. 1278 95

The regulatory role of nitric oxide (NO) in vaginal perfusion remains unclear. We used specific inhibitors of enzymes in the NO-cyclic GMP (NO-cGMP) pathway and investigated their effects on vaginal blood flow in the rabbit. NO synthase (NOS) activity was similar in both the proximal and distal rabbit vagina; whereas, arginase activity was 3.4-fold higher in the distal vagina. Intravenous administration of the NOS inhibitor L-NAME resulted in a 66% reduction in genital tissue oxyhemoglobin and a 53% reduction in vaginal blood flow. This attenuation occurred despite a 20-30% increase in systemic arterial pressure. The arginase inhibitor ABH caused a 2.1-fold increase in genital tissue oxyhemoglobin and 34% increase in vaginal blood flow. The guanylate cyclase inhibitor 1H-[1,2,4]oxadiazolo[4,3,-a]quinoxalin-1-one and the phosphodiesterase type 5 inhibitor sildenafil caused in a 37% reduction and a 44% increase in vaginal blood flow, respectively. These observations suggest that the NO-cGMP pathway is an important regulator of vaginal hemodynamics.
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PMID:Role of the nitric oxide-cyclic GMP pathway in regulation of vaginal blood flow. 1456 37