Control of noradrenaline release from hippocampal synaptosomes.
Potassium-evoked tritiated noradrenaline (NA) release from hippocampal synaptosomes was measured with a superfusion method. A single 2-min high-K+ pulse released 39% of the vesicular NA by a Ca2+-dependent mechanism: the Ca2+-independent release was negligible. After changing the vesicular NA store size by pretreating rats with either alpha-methyl-para-tyrosine, 500 mg/kg, or tranylcypromine, 10 mg/kg, a single K+ pulse released a constant percentage of the vesicular NA. With two K+ pulses, however, there was a reduction in the percentage of vesicular NA released in response to the second pulse.
D000818:Animals; D002118:Calcium / Q000494:pharmacology; D006624:Hippocampus / Q000378:metabolism*; D007700:Kinetics; D009638:Norepinephrine / Q000378:metabolism*; D011188:Potassium / Q000494:pharmacology; D051381:Rats; D013574:Synaptosomes / Q000187:drug effects / Q000378:metabolism*; D014316:Tritium
D014316:Tritium; D011188:Potassium; D002118:Calcium; D009638:Norepinephrine