Pharmacological control of muscular activity in the sea urchin larva--IV. Effects of monoamines and adenosine.
1. The muscular activity of the sea urchin pluteus is affected by catecholamines. alpha-Agonists in high concentrations bring about a strong, temporary, stimulation. 2. The stimulation by beta-agonists tends to be masked by different mechanisms. 3. Serotonin brings about a strong stimulation of long duration, even at 10(-7) M. It reactivates larvae where the activity has declined after exposure to catecholamines. A dopamine-effect at 10(-5)-5 x 10(-6) M is similar to that of serotonin. The effect of adenosine is similar to that of dc-c-AMP. 4. The action of the alpha- and beta-agonists and adenosine appears to involve an increased respectively excessive Ca2(+)-influx, directly or indirectly mediated by c-AMP. 5. It is suggested that a strong Ca2(+)-influx induces an outflux of K+ leading to hyperpolarization. Serotonin may decrease the K(+)-outflux.
Gustafson
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Wenner-Gren Institute, Arrhenius Laboratories F3, University of Stockholm, Sweden.
D000241:Adenosine / Q000494:pharmacology*; D000316:Adrenergic alpha-Agonists / Q000494:pharmacology; D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology; D000588:Amines / Q000494:pharmacology*; D000818:Animals; D002118:Calcium / Q000502:physiology; D002395:Catecholamines / Q000494:pharmacology / Q000502:physiology; D000242:Cyclic AMP / Q000502:physiology; D003995:Dibutyryl Cyclic GMP / Q000494:pharmacology; D004298:Dopamine / Q000494:pharmacology; D004789:Enzyme Activation; D005731:Ganglionic Stimulants / Q000494:pharmacology; D006162:Guanylate Cyclase / Q000378:metabolism; D007814:Larva; D009132:Muscles / Q000187:drug effects* / Q000502:physiology; D010243:Paralysis / Q000139:chemically induced; D010277:Parasympathomimetics / Q000494:pharmacology; D012617:Sea Urchins; D012701:Serotonin / Q000494:pharmacology; D013268:Stimulation, Chemical
D000316:Adrenergic alpha-Agonists; D000317:Adrenergic alpha-Antagonists; D000588:Amines; D002395:Catecholamines; D005731:Ganglionic Stimulants; D010277:Parasympathomimetics; D003995:Dibutyryl Cyclic GMP; D012701:Serotonin; D000242:Cyclic AMP; D006162:Guanylate Cyclase; D000241:Adenosine; D002118:Calcium; D004298:Dopamine