Alamethicin-evoked catecholamine release from cat adrenal glands.
Alamethicin enhances the rate of catecholamine output from perfused cat adrenal glands in a concentration-dependent manner. At 37 degrees C, catecholamine released went from 4.29 +/- 0.25 to 20.51 +/- 0.63 micrograms/stimulus at ionophore concentrations ranging from 20 to 100 micrograms/ml. Secretion was abolished at 22 degrees C or in the absence of extracellular Ca. The time-course of secretion (quick activation followed by a decline) evoked by alamethicin considerably differs from the catecholamine release pattern seen with A23187, X537A or ionomycin, which evoke a slowly developing, non-inactivating secretory response. In fact, its transient secretion pattern resembles that of nicotinic or high-K stimulation of cat adrenal glands, thus suggesting that alamethicin might form Ca permeable artificial channels in chromaffin cell plasma membranes.
Artalejo
A R
AR
Departamento de Ciencias Médicas Básicas, Facultad de Medicina de Lérida, Universidad de Barcelona, Spain.
Montiel
C
C
Sánchez-García
P
P
Uceda
G
G
Guantes
J M
JM
García
A G
AG
D000313:Adrenal Medulla / Q000378:metabolism*; D000408:Alamethicin / Q000494:pharmacology*; D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002118:Calcium / Q000502:physiology; D002395:Catecholamines / Q000378:metabolism*; D002415:Cats; D066298:In Vitro Techniques; D007476:Ionophores / Q000494:pharmacology; D012636:Secretory Rate / Q000187:drug effects; D012964:Sodium / Q000502:physiology; D013696:Temperature; D013779:Tetrodotoxin / Q000494:pharmacology; D013997:Time Factors
D000900:Anti-Bacterial Agents; D002395:Catecholamines; D007476:Ionophores; D000408:Alamethicin; D013779:Tetrodotoxin; D012964:Sodium; D002118:Calcium