Neuropharmacology and Neurotoxicology: PDF OnlyDifferent sensitivities to dihydropyridines of catecholamine release from cat and ox adrenalsGandía, Luis; Michelena, Pedro; de Pascual, Ricardp; Lopez, Manuela G.; García, Antonio G. Author Information Departamento de Farmacología y Terapéutica, Universidad Autónoma de Madrid, Facultad de Medicina, Arzobispo Morcillo s/n, 28029 Madrid, Spain NeuroReport: October 1990 - Volume 1 - Issue 2 - p 119-122 Buy Abstract CATECHOLAMINE release evoked by quick pulses of Ca2+ (2.5 mM) given sequentially at 30 min intervals to cat and ox adrenal glands perfused continuously with Ca2+ free Krebs-Tris solutions containing 35 or 118mM K+, was studied. In the feline, the secretory response was highly sensitive to various dihydropyridine (DHP) derivatives. For instance, secretion was completely blocked by nM concentrations of (+)isradipine (IC50 between 3 and 4 nM) and markedly potentiated by(-)Bay-K-8644. In contrast, the bovine secretory responses were resistant to blockade by nitrendipine or (+)isradipine, as well as to potentiation by Bay-K-8644, even at μM concentrations. From these experiments, it seems clear that distinct subtypes of Ca2+ channels might mediate a similar secretory response in ox and cat adrenal chromaffin cells, at least in the present experimental conditions. © Lippincott-Raven Publishers.