Depolarization-induced Ca2+ increase in isolated neurosecretory nerve terminals measured with fura-2.
The free Ca2+ concentration in isolated rat neurohypophysial nerve endings was measured using the Ca2+ indicator fura-2. Depolarization with high K, veratridine, or electrical stimulation induced an increase in intracellular Ca2+ concentration that was abolished by agents known to block voltage-sensitive Ca channels. Electrical stimulation of the isolated nerve endings with a pulse pattern similar to that recorded in vivo from the hypothalamic magnocellular neurons showed that the increase in intracellular Ca2+ concentration was not only a function of the applied frequency but also of the duration of the silent interburst intervals. The relationship between the cytoplasmic free Ca concentration and the release of neuropeptides is discussed.
Brethes
D
D
Dayanithi
G
G
Letellier
L
L
Nordmann
J J
JJ
D000818:Animals; D001572:Benzofurans; D002118:Calcium / Q000378:metabolism* / Q000494:pharmacology; D004558:Electric Stimulation; D005456:Fluorescent Dyes; D016257:Fura-2; D066298:In Vitro Techniques; D008297:Male; D009474:Neurons / Q000187:drug effects / Q000502:physiology; D009490:Neurosecretory Systems / Q000502:physiology*; D010904:Pituitary Gland, Posterior / Q000502:physiology*; D011188:Potassium / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D013050:Spectrometry, Fluorescence; D014701:Veratridine / Q000494:pharmacology
D001572:Benzofurans; D005456:Fluorescent Dyes; D014701:Veratridine; D011188:Potassium; D002118:Calcium; D016257:Fura-2