AJP - Endocrinology and Metabolism, Vol 244, Issue 6 560-E566, Copyright © 1983 by American Physiological Society
Dopamine stimulates somatostatin release from perifused hypothalamic cells
S. B. Richardson, T. Nguyen and C. S. Hollander
We studied the release of immunoreactive somatostatin (IR-SRIF) from
hypothalamic cells that were obtained from rats and dispersed with the aid
of collagenase. Twenty-four hours after dispersion, cells were placed in a
column supported by a matrix of preswollen Biogel P2 and perifused.
Fractions were collected on ice and subsequently assayed for SRIF. SRIF
release was stimulated markedly by potassium depolarization (KCl, 56 mM),
by the Na+-K+-ATPase inhibitor ouabain (10(-4) M), and by dopamine at
concentrations as low as 10(-11) M. The stimulatory effects of membrane
depolarization were calcium dependent and were not observed in the absence
of exogenous calcium in the perifusion medium or in the presence of EDTA
(0.05 M). Metoclopramide, the dopamine antagonist, abolished the
stimulatory effect of dopamine. In conclusion, release of IR-SRIF by
dispersed rat hypothalamic cells can be studied in a simple perifusion
apparatus. Release is stimulated by membrane depolarization in a
calcium-dependent manner and by dopamine at physiological concentrations.
