Effect of endothelin on Ca2+ influx, intracellular free Ca2+ levels and ligand binding to N and L type Ca2+ channels in rat brain.
The actions of endothelin, an endogenous vasoconstrictor compound with potent effects on various parameters of Ca2+ metabolism in peripheral tissue, were studied in several neuronal preparations. Endothelin, by itself, did not alter resting intracellular free Ca2+ levels or Ca2+ influx in either rat or chicken brain preparations; nor did it affect depolarization (K+) induced changes in these parameters. Endothelin also had no effect on the binding of [3H]-nitrendipine or [125I]-omega-conotoxin to "L " or "N" type channels respectively nor did it induce the release of endogenous acetylcholine from brain slices. The results show that, despite the proposed role of endothelin on voltage sensitive Ca2+ channels in peripheral tissue and despite the existence of endothelin binding sites on both smooth muscle and neurons, endothelin has no measurable effects on Ca2+ metabolism in neural tissue of central origin.
Hamilton
M G
MG
Biomedical Defence Section Defence Research Establishment Suffield Ralston, Alberta, Canada.
Frew
R
R
Lundy
P M
PM
D000109:Acetylcholine / Q000378:metabolism; D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D001921:Brain / Q000502:physiology*; D002118:Calcium / Q000378:metabolism*; D015220:Calcium Channels / Q000145:classification / Q000187:drug effects / Q000378:metabolism*; D003593:Cytoplasm / Q000378:metabolism; D016232:Endothelins; D066298:In Vitro Techniques; D009474:Neurons / Q000502:physiology; D010455:Peptides / Q000494:pharmacology*; D051381:Rats; D013574:Synaptosomes
D015220:Calcium Channels; D016232:Endothelins; D010455:Peptides; D000109:Acetylcholine; D002118:Calcium