Low Ca2+ plus tetraethylammonium medium: its usefulness in studying the effect of Ca antagonist on adrenergic neurotransmission.
The low Ca2+ + tetraethylammonium (TEA) medium enhanced electrically evoked norepinephrine release by 3.5-fold in canine saphenous veins. omega-Conotoxin GVIA (omega-CTX) inhibited the neurotransmission more markedly in low Ca2+ + TEA medium than in normal Krebs medium. This is the case for the inhibition by tetrodotoxin, though to a lesser extent. The inhibition by omega-CTX was competitively antagonized by elevating external Ca2+. The results indicate that low Ca2+ + TEA medium is useful for studying the effect of Ca antagonists on adrenergic neurotransmission, because omega-CTX acts more effectively in this medium.
Takata
Y
Y
Department of Pharmacology, Faculty of Pharmaceutical Sciences, Teikyo University, Kanagawa, Japan.
Ozawa
J
J
Kato
H
H
D000818:Animals; D002118:Calcium / Q000737:chemistry*; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D004285:Dogs; D004558:Electric Stimulation; D009638:Norepinephrine / Q000378:metabolism*; D010456:Peptides, Cyclic / Q000494:pharmacology*; D012501:Saphenous Vein / Q000187:drug effects / Q000378:metabolism; D009435:Synaptic Transmission / Q000187:drug effects*; D019789:Tetraethylammonium; D013757:Tetraethylammonium Compounds / Q000737:chemistry*; D013779:Tetrodotoxin / Q000494:pharmacology; D020866:omega-Conotoxin GVIA
D002121:Calcium Channel Blockers; D010456:Peptides, Cyclic; D013757:Tetraethylammonium Compounds; D013779:Tetrodotoxin; D019789:Tetraethylammonium; D020866:omega-Conotoxin GVIA; D002118:Calcium; D009638:Norepinephrine