Premium
Possible Involvement of Inhibitory GTP Binding Regulatory Protein in α 2 ‐Adrenoceptor‐Mediated Inhibition of Adenylate Cyclase Activity in Cerebral Cortical Membranes of Rats
Author(s) -
Kitamura Yoshihisa,
Nomura Yasuyuki,
Segawa Tomio
Publication year - 1985
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1985.tb07219.x
Subject(s) - adenylate kinase , cyclase , cholera toxin , gtp' , forskolin , g protein , pertussis toxin , chemistry , medicine , endocrinology , biochemistry , biology , receptor , enzyme
Influences of α 2 ‐adrenoceptor stimulation on adenylate cyclase activity were investigated in cerebral cortical membranes of rats. Pretreatment of the membranes with islet‐activating protein and NAD resulted in a significant increase in basal activity as well as in GTP‐or forskolin/GTP‐induced elevation of adenylate cyclase activity. Strong activation of adenylate cyclase was also caused in membranes pretreated with cholera toxin together with NAD in comparison to that in control membranes, suggesting that adenylate cyclase activity is perhaps regulated by stimulatory and inhibitory GTP binding regulatory protein existing in synaptic membranes. In addition, adrenaline (with propranolol) or clonidine significantly reduced adenylate cyclase activity stimulated by pretreatment with forskolin and GTP. The inhibitory effects of adrenaline were also observed in membranes pretreated with cholera toxin and NAD. Moreover, the inhibition by adrenaline or clonidine was completely abolished by treatment with (a) yohimbine or (b) islet‐activating protein and NAD. It is suggested that α‐receptor stimulation causes inhibitory influences on adenylate cyclase activity mediated by the inhibitory GTP binding regulatory protein in synaptic membranes of rat cerebral cortex.