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The effects of Mn2+ and calmodulin were studied on the basal and agonist-modulated adenylate cyclase activity of the guinea pig superior cervical ganglion. The divalent cation strongly stimulates the basal and agonist-modulated enzyme in a concentration-dependent manner. Moreover, in the presence of Mn2+ the inhibitory effects of "high" GTP concentrations and of D-Ala2-Met-enkephalinamide on adenylate cyclase are eliminated, while the stimulation exerted by prostaglandin E2 and the supra-additive activation of the enzyme by the combination of the two drugs are unaffected. In EGTA-washed, calmodulin-depleted membrane preparations, Mn2+ still activates the cyclase but the enkephalin inhibition and the superactivation of the enzyme induced by the combination of opiate and prostaglandin are lost, both in the absence and in the presence of the cation. Reconstituting the depleted membranes with exogenous Ca2+/calmodulin fully restored the enzyme responsivity to the combination and, partially, to the enkephalin. The findings suggest the existence in the guinea pig superior cervical ganglion of both the calmodulin-sensitive and differently regulated calmodulin-insensitive adenylate cyclase.
M E Ferretti, and
P G Borasio, and
C Biondi, and
A L Campi, and
M C Pareschi, and
A Portolan
November 1996,
Neuroreport,
M E Ferretti, and
P G Borasio, and
C Biondi, and
A L Campi, and
M C Pareschi, and
A Portolan
November 1988,
Neurochemical research,
M E Ferretti, and
P G Borasio, and
C Biondi, and
A L Campi, and
M C Pareschi, and
A Portolan
October 1980,
European journal of pharmacology,
M E Ferretti, and
P G Borasio, and
C Biondi, and
A L Campi, and
M C Pareschi, and
A Portolan
September 1983,
Journal of neurochemistry,
M E Ferretti, and
P G Borasio, and
C Biondi, and
A L Campi, and
M C Pareschi, and
A Portolan
September 1989,
Neuroscience letters,
M E Ferretti, and
P G Borasio, and
C Biondi, and
A L Campi, and
M C Pareschi, and
A Portolan
January 1986,
European journal of biochemistry,
M E Ferretti, and
P G Borasio, and
C Biondi, and
A L Campi, and
M C Pareschi, and
A Portolan
January 1980,
Annals of the New York Academy of Sciences,
M E Ferretti, and
P G Borasio, and
C Biondi, and
A L Campi, and
M C Pareschi, and
A Portolan
July 1983,
Biochimica et biophysica acta,
M E Ferretti, and
P G Borasio, and
C Biondi, and
A L Campi, and
M C Pareschi, and
A Portolan
October 1976,
FEBS letters,
M E Ferretti, and
P G Borasio, and
C Biondi, and
A L Campi, and
M C Pareschi, and
A Portolan
June 1987,
The Journal of biological chemistry,
