Calcium mechanism of norepinephrine activation of ionic pump in somatic cells of lumbricus terrestris earthworm muscle wall.
Blockade of norepinephrine-induced hyperpolarization in earthworm muscle cells was observed in a calcium-free medium, after substitution of Ca(2+)with Mn(2+), and in the presence of verapamil or chlorpromazine to the incubation saline. Changes in Ca(2+)concentration in the saline and addition of caffeine had no effect on the resting potential of muscle cells. It was hypothesized that signal transduction from norepinephrine-activated membrane adrenoceptors to the ionic pump in earthworm muscle cells depends on influx of extracellular Ca(2+)and subsequent involvement of Ca(2+)-accepting proteins similar to calmodulin in vertebrates.
Volkov
E M
EM
Kazan' State Medical University. emvolkov@kzn.ru
Nurullin
L F
LF
Obukhova
A S
AS
Chikin
A V
AV
Nikol'skii
E E
EE
D000316:Adrenergic alpha-Agonists / Q000737:chemistry; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D007477:Ions; D008345:Manganese / Q000378:metabolism; D009132:Muscles / Q000378:metabolism* / Q000502:physiology*; D009638:Norepinephrine / Q000494:pharmacology*; D009835:Oligochaeta; D011941:Receptors, Adrenergic / Q000378:metabolism
D000316:Adrenergic alpha-Agonists; D007477:Ions; D011941:Receptors, Adrenergic; D008345:Manganese; D002118:Calcium; D009638:Norepinephrine