Characterization of the Ca2+ Response Mediated by Activation of β-Adrenoceptors in Rat Submandibular Ducts

The Japanese Journal of Pharmacology

Akihiko Tanimura¹  Akihiro Nezu¹  Yosuke Tojyo¹ 

[1] Department of Dental Pharmacology,School of Dentistry,Health Sciences University of Hokkaido,Ishikari--Tobetsu,Hokkaido 061-0293,Japan

关键词: Submandibular duct;    β-Adrenoceptor;    Cytosolic Ca2+;    Isoproterenol;    Cyclic AMP;   

DOI  :  10.1254/jjp.84.25

学科分类：药理学

来源: Nihon Yakuri Gakkai Henshuubu / Japanese Pharmacological Society

【 摘 要 】

References(19)Cited-By(2)The Ca2+ signaling mediated by activation of β−adrenoceptors was studied in a purified preparation of ducts from rat submandibular glands.At concentrations above 1 nM, isoproterenol(ISO)caused a small but significant increase in cytosolic Ca2+ concentration([Ca2+]i).The ISO−induced increase in [Ca2+]i was completely inhibited by the β−adrenoceptor antagonist propranolol but not by the α−adrenoceptor antagonist phentolamine.Forskolin was able to mimic the Ca2+ response to ISO.These results suggest that the ISO−induced increase in [Ca2+]i in rat submandibular ducts is mediated by an accumulation of cAMP resulting from activation of β−adrenoceptors.In the absence of extracellular Ca2+, ISO or forskolin caused a transient increase in [Ca2+]i, indicating Ca2+ mobilization from intracellular Ca2+ stores.Further, stimulation with ISO failed to mobilize Ca2+ after the depletion of intracellular Ca2+ stores by phenylephrine or carbachol, suggesting that the cAMP−mediated increase in [Ca2+]i is due to a Ca2+ release from inositol trisphosphate(IP3)−sensitive Ca2+ stores.As ISO did not stimulate a detectable production of IP3, the cAMP−mediated Ca2+ mobilization may be evoked by a mechanism different from activation of phosphoinositide hydrolysis.

【 授权许可】

Unknown