Effects of tetrodotoxin, elevated calcium and calcium antagonists on electrically induced 3H-noradrenaline release from brain slices.
Electrically induced release of 3H-noradrenaline from superfused rat brain cortex slices was completely inhibited by tetrodotoxin (1 microgram/ml) if 0.5 or 1 V stimuli were used, while inhibition was 97% with 2 V, and nil with 12 V stimuli. 20 mM calcium depressed noradrenaline release at all applied potentials, and shifted the release versus voltage curve to higher potentials. Manganese (5 mM) and D-600 (10-100 microgram/ml) also considerably inhibited release. This suggests that stimuli of up to 2 V induce transmitter release by exciting intracortical noradrenergic axons in their non-terminal regions.
D000818:Animals; D001921:Brain / Q000187:drug effects / Q000378:metabolism*; D002118:Calcium / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D004558:Electric Stimulation; D005711:Gallopamil / Q000494:pharmacology; D066298:In Vitro Techniques; D008345:Manganese / Q000494:pharmacology; D009638:Norepinephrine / Q000378:metabolism*; D051381:Rats; D013779:Tetrodotoxin / Q000494:pharmacology*; D013997:Time Factors
D005711:Gallopamil; D008345:Manganese; D013779:Tetrodotoxin; D002118:Calcium; D009638:Norepinephrine