Details

Autor(en) / Beteiligte

• Yousif, F B
• Bolger, G T
• Ruzycky, A
• Triggle, D J

Titel

Ca2+ channel antagonist actions in bladder smooth muscle: comparative pharmacologic and [3H]nitrendipine binding studies

Ist Teil von

• Canadian journal of physiology and pharmacology, 1985-05, Vol.63 (5), p.453

Ort / Verlag

Canada

Erscheinungsjahr

1985

Link zum Volltext

Quelle

MEDLINE

Beschreibungen/Notizen

• The actions of a series of 15 Ca2+ channel antagonists including D-600, nifedipine, and diltiazem were examined against K+ depolarization and muscarinic receptor induced responses in guinea pig bladder smooth muscle. Responses of bladder are very dependent upon extracellular Ca2+ and sensitive to the Ca2+ channel antagonists, the tonic component more than the phasic component of response. Regardless of stimulant, K+ or methylfurmethide (MF), or component of response, the same rank order of antagonist activities is expressed, suggestive of a single structure-activity relationship and the existence of a single category of binding site which may, however, exist in several affinity states. High affinity binding of [3H]nitrendipine (KD = 1.1 X 10(-10) M) occurs in bladder membranes, and similar high affinity binding was found in microsomal preparations from other smooth muscles including guinea pig and rat lung, rat vas deferens, uterus, and stomach. [3H]nitrendipine binding in the bladder was sensitive to displacement by other 1,4-dihydropyridines, paralleling their pharmacologic activities and showing excellent agreement with binding data previously obtained for guinea pig ileal smooth muscle. Comparison of pharmacologic data for inhibition of K+- and MF-induced responses by a common series of Ca2+ channel antagonists in bladder and ileum revealed excellent correlations. Neither pharmacologic nor binding studies suggest significant differences in Ca2+ channel antagonist properties in smooth muscle from bladder and intestine.