CYCLIC-AMP LINKS AMINO-ACID CHEMORECEPTORS TO ION CHANNELS IN OLFACTORY CILIA
CYCLIC-AMP LINKS AMINO-ACID CHEMORECEPTORS TO ION CHANNELS IN OLFACTORY CILIA
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DOI：
10.1093/chemse/15.4.419
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发表时间：
1990-10-01
期刊：
影响因子：
3.5
通讯作者：
TEETER, JH
中科院分区：
文献类型：
--
作者：
BRUCH, RC;TEETER, JH
研究了刺激斑点叉尾斑点叉尾鱼嗅觉的氨基酸对分离的嗅觉纤毛环磷酸腺苷代谢的影响。代表每种受体亚型的10种刺激，转换了广泛的电生理效力，在依赖鸟嘌呤核苷酸的环状AMP形成中引起了类似的增加。只有当受体占有率接近或超过50%时，才能观察到腺苷环化酶的刺激依赖性激活。腺苷环化酶的刺激激活与单独用鸟嘌呤核苷酸获得的刺激激活是相加的，不依赖于受体的特异性，与神经功能的相关性较差。刺激物不影响分离纤毛制剂中的环核苷酸磷酸二酯酶活性。环化AMP和环化GMP都可逆地增加人工磷脂双层中的纤毛膜电导。环核苷酸门控电导可被同等效力的核苷酸激活，不需要外源ATP或GTP，并由44pS非选择性阳离子通道介导。综上所述，这些结果表明，在适当的受体占位条件下，cAMP通过直接门控嗅觉纤毛的阳离子通道，将氨基酸化学受体与膜去极化联系起来。
Amino acids, olfactory stimuli for the channel catfish (Ictalurus Punctatus), were tested for the ability to affect cyclic AMP metabolism in isolated olfactory cilia. Ten stimuli, representative of each receptor subtype and convering a wide range of electrophysiological potency, elicited similar increases in guanine nucleotide-dependent cyclic AMP formation. Stimulus-dependent activation of adenylate cyclase was observed only when receptor occupancy approached or exceeded 50%. Stimulus activation of adenylate cyclase was additive with that obtained with guanine nucleotide alone, was independent of receptor specificity, and poorly correlated with neural potency. Stimuli did not affect cyclic nucleotide phosphodiesterase activity in isolated cilia preparations. Both cyclic AMP and cyclic GMP reversibly increased membrane conductance in isolated ciliary membranes incorporated in artificial phospholipid bilayers. The cyclic nucleotide-gated conductance was activated by either nucleotide with equal potency, did not require exogenous ATP or GTP, and was mediated by 44 pS non-selective cation channels. Taken together, these results suggest that, under appropriate conditions of receptor occupancy, cyclic AMP links amino acid chemoreceptor binding to membrane depolarization by directly gating cation channels in olfactory cilia.