ISSN:
1434-0879
Keywords:
Penile erection
;
Smooth muscle
;
Calcium channel blocker
;
Intracellular calcium
;
Ryanodine
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Abstract Norepinephrine release from adrenergic nerve terminals leads to a rise in intracellular Ca2+, which promotes penile smooth muscle contraction and detumescence. Ca2+ sources are the extracellular space and sarcoplasmic Ca2+ stores. To elucidate the role of intracellular stores strips from rabbit erectile tissue were investigated in an organ bath study. Contractions were elicited by phenylephrine (PE) and electrical stimulation. Incubation in Ca2+-free solution as well as exposure to nifedipine did not abolish electrical or PE-induced contraction. Ryanocline (10-5 mol/l), a functional blocker of sarcoplasmic Ca2+ channels, significantly reduced PE response. In the presence of caffeine (10-3 mol/l) the effect was significantly enhanced. Addition of nifedipine nearly abolished the contraction. These results provide evidence for intracellular Ca2+ pools in cavernosal tissue and indicate that the α1-adrenoceptor-induced contraction requires the opening of voltage-gated Ca2+ channels and the release of Ca2+ from intracellular stores.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00296883
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