Involvement of Extracellular Calcium and Arachidonate in [3H] Dopamine Release from Rat Tuberoinfundibular Neurons
- 1 January 1989
- journal article
- research article
- Published by S. Karger AG in Neuroendocrinology
- Vol. 50 (4) , 481-487
- https://doi.org/10.1159/000125267
Abstract
The mechanism of [3H]dopamine ([3H]DA) release was investigated using primary cultures of dispersed cells from the rat tuberoinfundibular region, which contains tyrosine hydroxylase (TH)-like immunoreactive neurons. The calcium ionophore A23187 at 10 nM and above caused a significant and dose-dependent increase in [3H]DA release. In the presence of 50 µM A23187, [3H]DA release was detectable within 30 s and reached a plateau in 15 min. The induction of [3H]DA release by 50 µM A23187 was abolished by lowering the extracellular calcium concentration with 2 mM EDTA. Maitotoxin, another calcium-channel activator, also increased [3H]DA release at a concentration of 50 ng/ml. Exogenous additions of 100 mlU/ml phospholipase A2 and 10 µM arachidonate caused significant release of [3H]DA. Furthermore, A23187 stimulated [3H]arachidonate release from tuberoinfundibular dopaminergic (ΗDA) neurons in a dose- and time-dependent manner. These results suggest that extracellular calcium and arachidonate are involved in the process of [3H]DA release from rat ΗDA neurons.Keywords
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