Evidence for two types of nicotinic receptors in the cat carotid body chemoreceptor cells

详细信息    查看全文

• 作者：Obeso ; Ana ; Gó ; mez-Ni&ntilde ; o ; Marí ; a Angeles ; Almaraz ; Laura ; Dinger ; Bruce ; et. al.
• 关键词：Carotid body ; Nicotinic receptor ; Nicotine ; α ; -Bungarotoxin ; Catecholamine
• 刊名：Brain Research
• 出版年：1997
• 出版时间：April 18, 1997
• 年：1997
• 卷：754
• 期：1-2
• 页码：298-302
• 全文大小：192 K

文摘

Current concepts on the location and functional significance of nicotinic receptors in the carotid body rest on α-bungarotoxin binding and autoradiographic studies. Using an in vitro preparation of the cat carotid body whose catecholamine deposits have been labeled by prior incubation with the tritiated natural precursor [³H]tyrosine, we have found that nicotine induces release of [³H]catecholamines in a dose-dependent manner (IC₅₀=9.81 μM). We also found that mecamylamine (50 μM) completely abolished the nicotine-induced release, while α-bungarotoxin (100 nM; ≈20 times its binding K_d) only reduced the release by 56 % . These findings indicate that chemoreceptor cells, and perhaps other carotid body structures, contain nicotinic receptors that are not sensitive to α-bungarotoxin and force a revision of the current concepts on cholinergic mechanisms in the carotid body chemoreception.