title: Effects of noradrenaline on cytosolic concentrations of Ca(2+) in cultured corpus cavernosum smooth muscle cells of the rabbit.
abstract: An immunohistochemical examination of cultured corpus cavernosum cells of the rabbit showed that they were composed of many smooth muscle cells retaining -smooth muscle actin and a few of endothelial cells. Application of noradrenaline (NA, 0.5-100 microM) to the culture dose-dependently increased cytosolic concentrations of Ca2+ ([Ca2+]i) in smooth muscle cells. The NA (10 microM)-induced [Ca2+]i increase was dose-dependently inhibited by phenoxybenzamine (1 nM-1 microM). The inhibition was 71% at 0.1 microM and was completely made at 1 microM. An alpha(1)-adrenoceptor antagonist, prazosin (0.1 microM), inhibited the [Ca2+]i response by 42%, and propranolol (1 microM) enhanced the response by 118%. These adrenoceptor antagonists showed almost the same effects on a contractile response of corporal tissue strips to NA (10 microM) as the effects on the [Ca2+]i response. Our results suggest that NA-induced [Ca2+]i increase was mixed with a large increase through 1-adrenoceptors and a small decrease through beta-adrenoceptors. The increased [Ca2+]i could play a role of intracellular messenger for leading to contraction of cavernosal smooth muscle cells.
authors: Department of Physiology, Akita University School of Medicine, 1-1-1 Hondo, Akita 010-8543, Japan. minoru@med.akita-u.ac.jp
authors: Minoru
authors: M
authors: Sato
authors: Masahito
authors: M
authors: Kawatani
mesh_terms: D000199:Actins / Q000378:metabolism; D058646:Adrenergic alpha-1 Receptor Agonists; D058668:Adrenergic alpha-1 Receptor Antagonists; D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology; D000319:Adrenergic beta-Antagonists / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D020013:Calcium Signaling / Q000187:drug effects / Q000502:physiology*; D002478:Cells, Cultured; D003600:Cytosol / Q000187:drug effects / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D005455:Fluorescent Antibody Technique; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects / Q000502:physiology; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000294:innervation / Q000378:metabolism*; D009638:Norepinephrine / Q000378:metabolism* / Q000494:pharmacology; D010410:Penile Erection / Q000187:drug effects / Q000502:physiology; D010413:Penis / Q000098:blood supply* / Q000166:cytology / Q000294:innervation*; D010643:Phenoxybenzamine / Q000494:pharmacology; D011224:Prazosin / Q000494:pharmacology; D011433:Propranolol / Q000494:pharmacology; D011817:Rabbits; D018340:Receptors, Adrenergic, alpha-1 / Q000378:metabolism; D011943:Receptors, Adrenergic, beta / Q000187:drug effects / Q000378:metabolism; D017779:Sympathetic Fibers, Postganglionic / Q000378:metabolism*
chemical_list: D000199:Actins; D058646:Adrenergic alpha-1 Receptor Agonists; D058668:Adrenergic alpha-1 Receptor Antagonists; D000317:Adrenergic alpha-Antagonists; D000319:Adrenergic beta-Antagonists; D018340:Receptors, Adrenergic, alpha-1; D011943:Receptors, Adrenergic, beta; D010643:Phenoxybenzamine; D011433:Propranolol; D002118:Calcium; D009638:Norepinephrine; D011224:Prazosin