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Query: EC:4.6.1.1 (
adenylate cyclase
)
19,190
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
Effects of 5-hydroxytryptamine (5-HT) and forskolin on intracellular free calcium concentration [( Ca2+]i) were studied in suspensions of fura-2 loaded smooth-muscle cells from the anterior byssus retractor 'catch' muscle of Mytilus edulis. The successive addition of 5 mM carbachol (CCh) and 100 mM KCl to the suspension evoked a transient elevation of [Ca2+]i from the resting value of 124 +/- 2.7 nM (mean +/- SE, n = 18) to 300-400 nM, which was associated with contraction. The change in [Ca2+]i induced CCh was concentration-dependent with the EC50 of 10(-5) M. The resting [Ca2+]i was unaffected by 10 microM 5-HT. The change in [Ca2+]i induced by 5 mM CCh was suppressed by 5-HT from 167 +/- 14.0 (n = 11) to 124 +/- 14.9 (n = 8) nM whereas that induced by 100 mM KCl was enhanced from 321 +/- 31.9 to 405 +/- 17.6 nM (n = 8). 5-HT applied during the decaying phase of the CCh response caused a rapid decline in [Ca2+]i. In both the responses to CCh and KCl, the falling phase was accelerated by 5-HT. 10 microM forskolin, a potent activator of
adenylate cyclase
, mimicked the effects of 5-HT as did a membrane-permeant cyclic AMP analogue, 8-parachlorophenylthio cyclic AMP (cpt-cAMP). Application of 100 microM cpt-cAMP partially suppressed the Ca2+i response to CCh and enhanced that to KCl.
D-Tubocurarine
(500 microM) added during the decaying phase of the response induced by 100 microM CCh, caused a rapid decline in [Ca2+]i similar to that caused by both 5-HT and forskolin.(ABSTRACT TRUNCATED AT 250 WORDS)
...
PMID:Effects of 5-hydroxytryptamine (serotonin) and forskolin on intracellular free calcium in isolated and fura-2 loaded smooth-muscle cells from the anterior byssus retractor (catch) muscle of Mytilus edulis. 275 71
Adenylate cyclase in Drosophila melanogaster heads is stimulated 5-6-fold by low concentrations of octopamine. The octopamine stimulation is inhibited by low concentrations of the alpha-adrenergic ligands phentolamine and dihydroergotamine and of chlorpromazine, but not by low concentrations of the beta-antagonist propranolol and by the alpha-antagonist yohimbine. d-
Tubocurarine
enhances the octopamine effect. Tyramine, norepinephrine, and epinephrine also stimulate the cyclase, probably via the octopamine receptor. Serotonin and dopamine stimulate Drosophila adenylate cyclase 1.3-1.4-fold; at least the latter putative neurotransmitter seems to interact with a receptor distinct from the octopamine receptor. Prolonged incubation with dopamine in vitro abolishes
adenylate cyclase
basal activity as well as responsiveness to guanyl nucleotides, NaF, and putative neurotransmitters.
...
PMID:Aminergic receptors in Drosophila melanogaster: responsiveness of adenylate cyclase to putative neurotransmitters. 612 19
1 The possibility that cyclic adenosine 3',5'-monophosphate (cyclic AMP) mediates a voltage-dependent inward current elicited by 5-hydroxytryptamine (5-HT) in RB and LB cells of the abdominal ganglion of Aplysia was tested. 2 Intracellular injection of cyclic AMP elicited an inward current with a similar time course, potential dependence and ionic sensitivity as the response to 5-HT. 3 Intracellular injection of guanylyl imidodiphosphate (GMP-PNP), which activated
adenylate cyclase
, neither mimicked nor enhanced the 5-HT-evoked current. On the contrary, it reduced the current. 4 The phosphodiesterase inhibitors, Ro20-1724, isobutyl methylxanthine (IBMX) and theophylline, each antagonized the voltage-dependent response to 5-HT. To varying degrees they each induced an inward current. 5 The
adenylate cyclase
antagonist, dithiobisnitrobenzoic acic (DTNB), had no effect on the response to 5-HT when applied either intracellularly or extracellularly. Intracellular injection of the phosphodiesterase activator imidazole also had no effect. 6
Tubocurarine
and neostigmine did not reduce the voltage-dependent inward current evoked by 5-HT; methysergide elicited an inward current. 7 Although the observations that cyclic AMP and 5-HT can evoke similar voltage-dependent inward currents in RB and LB neurones of Aplysia might suggest a second messenger role for the cyclic nucleotide, the pharmacological data are inconsistent with this hypothesis.
...
PMID:Does cyclic 3' ,5'-adenosine monophosphate act as second messenger in a voltage-dependent response to 5-hydroxytryptamine in Aplysia? 617 22