Toosendanin facilitates [3H]noradrenaline release from rat hippocampal slices.
Slices of hippocampus of the rat, preincubated with [3H]noradrenaline ([3H]NA), were used to investigate the effects of toosendanin on the release of [3H]NA. Toosendanin potently enhanced spontaneous 3H outflow. Seventy-four percent of the enhancement was inhibited by reserpine pretreatment. The toosendanin-induced 3H overflow was in a concentration-dependent manner (5-60 microM) both in the presence and absence of extracellular calcium. Under Ca(2+)-free conditions, the effect of toosendanin on 3H outflow was unchanged by TTX, but inhibited by Ca(2+)-chelator BAPTA-AM; dantrolene sodium failed to affect the toosendanin-induced 3H outflow, while 3,4-diaminopyridine showed an additive effect on the outflow with this substance. The findings suggest that in the absence of extracellular Ca2+, toosendanin enhances [3H]NA release through the liberation of intracellular Ca2+ stores.
Hua-Yu
H
H
Shanghai Institute of Physiology, Chinese Academy of Sciences, China.
Cheng-Wen
Z
Z
Yu-Liang
S
S
D015761:4-Aminopyridine / Q000031:analogs & derivatives / Q000494:pharmacology; D000077770:Amifampridine; D000818:Animals; D002118:Calcium / Q000378:metabolism; D002614:Chelating Agents / Q000494:pharmacology; D003620:Dantrolene / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004365:Drugs, Chinese Herbal / Q000633:toxicity*; D004533:Egtazic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D006624:Hippocampus / Q000187:drug effects* / Q000378:metabolism; D066298:In Vitro Techniques; D007553:Isotope Labeling; D009125:Muscle Relaxants, Central / Q000494:pharmacology; D009466:Neuromuscular Blocking Agents / Q000633:toxicity*; D009638:Norepinephrine / Q000378:metabolism*; D015221:Potassium Channels / Q000187:drug effects; D051381:Rats; D017207:Rats, Sprague-Dawley; D012110:Reserpine / Q000494:pharmacology; D013565:Sympatholytics / Q000494:pharmacology; D014316:Tritium; D014315:Triterpenes
D015761:4-Aminopyridine; D000077770:Amifampridine; D002118:Calcium; D002614:Chelating Agents; D003620:Dantrolene; D004365:Drugs, Chinese Herbal; D004533:Egtazic Acid; D009125:Muscle Relaxants, Central; D009466:Neuromuscular Blocking Agents; D009638:Norepinephrine; D015221:Potassium Channels; D012110:Reserpine; D013565:Sympatholytics; D014316:Tritium; C070379:1,2-bis(2-aminophenoxy)ethane N,N,N',N'-tetraacetic acid acetoxymethyl ester; C036454:toosendanin; D014315:Triterpenes