Park T J, Seo H K, Kang B J, Kim K T
Department of Life Science, Division of Molecular and Life Science, Pohang University of Science and Technology, San 31, Hyoja Dong, 790-784, Pohang, Korea.
Biochem Pharmacol. 2001 Apr 1;61(7):787-93. doi: 10.1016/s0006-2952(01)00547-0.
The effect of camphor, a monoterpenoid, on catecholamine secretion was investigated in bovine adrenal chromaffin cells. Camphor inhibited [3H]norepinephrine ([3H]NE) secretion induced by a nicotinic acetylcholine receptor (nAChR) agonist, 1,1-dimethyl-4-phenylpiperazinium iodide (DMPP), with a half-maximal inhibitory concentration (IC50) of 70 +/- 12 microM. In addition, camphor inhibited the rise in cytosolic calcium ([Ca2+]i) and sodium ([Na+]i) induced by DMPP with IC50 values of 88 +/- 32 and 19 +/- 2 microM, respectively, suggesting that the activity of nAChRs is also inhibited by camphor. On the other hand, binding of [3H]nicotine to nAChRs was not affected by camphor. [Ca2+]i increases induced by high K+, veratridine, and bradykinin were not affected by camphor. The data suggest that camphor specifically inhibits catecholamine secretion by blocking nAChRs without affecting agonist binding.
研究了单萜类化合物樟脑对牛肾上腺嗜铬细胞儿茶酚胺分泌的影响。樟脑抑制了烟碱型乙酰胆碱受体（nAChR）激动剂1,1-二甲基-4-苯基哌嗪碘化物（DMPP）诱导的[3H]去甲肾上腺素（[3H]NE）分泌，其半数最大抑制浓度（IC50）为70±12微摩尔。此外，樟脑抑制了DMPP诱导的细胞内钙（[Ca2+]i）和钠（[Na+]i）浓度升高，IC50值分别为88±32和19±2微摩尔，这表明nAChRs的活性也受到樟脑的抑制。另一方面，[3H]尼古丁与nAChRs的结合不受樟脑影响。高钾、藜芦碱和缓激肽诱导的[Ca2+]i升高不受樟脑影响。数据表明，樟脑通过阻断nAChRs特异性抑制儿茶酚胺分泌，而不影响激动剂结合。
