CYCLIC-AMP MEDIATES INHIBITION OF THE NA+-K+ ELECTROGENIC PUMP BY SEROTONIN IN TACTILE SENSORY NEURONS OF THE LEECH
CYCLIC-AMP MEDIATES INHIBITION OF THE NA+-K+ ELECTROGENIC PUMP BY SEROTONIN IN TACTILE SENSORY NEURONS OF THE LEECH
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DOI：
10.1113/jphysiol.1993.sp019552
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发表时间：
1993-03-01
影响因子：
5.5
通讯作者：
BRUNELLI, M
中科院分区：
文献类型：
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作者：
CATARSI, S;SCURI, R;BRUNELLI, M
1.5-羟色胺(5-HT)可降低水蚤触觉感觉神经元(T)的后超极化(AHP)波幅，但对升压(P)和伤害性感觉(N)细胞无影响。腺苷环化酶激动剂、磷酸二酯酶抑制剂和环磷酸腺苷(CAMP)的膜类似物可模拟5-羟色胺降低T神经元AHP幅度的作用。T细胞内离子导入环磷酸腺苷(CAMP)可降低AHP波幅，而环鸟苷(CGMP)或腺苷-5‘-一磷酸(AMP)对此无影响。药物RMI 12330A(也称为MDL 12330A)对腺苷环化酶的抑制表明，5-羟色胺通过环化AMP降低了AHP的幅度。8-溴腺苷-3‘-5’-环磷酸腺苷(8-BR-cAMP)在用氯化镉阻断钙激活的K+电导后，仍能降低AHP的幅度，并将细胞内注入Na+后的正常超极化转变为去极化。此外，在T感觉神经元中，环状AMP类似物可使无K+溶液灌流后CSCL引起的复极化减慢和减弱。推测在T感觉神经元中，环状AMP介导了5-羟色胺对Na+-K+生电泵的抑制作用。
1. Serotonin (5-HT) reduced the after-hyperpolarization (AHP) amplitude in tactile sensory neurones (T) but not in pressor (P) or nociceptive (N) cells of the leech.2. Adenylate cyclase activators, phosphodiesterase inhibitors and membrane permeant analogues of cyclic adenosine monophosphate (cyclic AMP) mimicked the effect of 5-HT in reducing the AHP amplitude in T neurones.3. Ionophoretic injection of cyclic AMP in T cells reduced the AHP amplitude, while cyclic guanosine monophosphate (cyclic GMP) or adenosine-5'-monophosphate (AMP) were without effect.4. Inhibition of adenylate cyclase by the drug RMI 12330A (also known as MDL 12330A) suggested that 5-HT reduced the AHP amplitude through cyclic AMP.5. 8-Bromoadenosine-3'-5'-cyclic monophosphate (8-Br-cyclic AMP) was still able to reduce the AHP amplitude after blocking the Ca2+-activated K+ conductance with CdCl2 and converted the normal hyperpolarization which follows the intracellular injection of Na+ into a depolarization. In addition, the cyclic AMP analogue slowed down and reduced the repolarization usually induced by CsCl after perfusion with K+-free solution.It is proposed that, in T sensory neurones, cyclic AMP mediates the inhibition of the Na+-K+ electrogenic pump induced by 5-HT application.