LARGE AND SMALL VERTEBRATE SENSORY NEURONS EXPRESS DIFFERENT NA-CHANNEL AND K-CHANNEL SUBTYPES

被引:40
作者
CAMPBELL, DT
机构
[1] Hatfield Marine Science Center, Oregon State University, Newport
关键词
TETRODOTOXIN-RESISTANT; DORSAL ROOT GANGLION; ACTION POTENTIAL; PATCH CLAMP;
D O I
10.1073/pnas.89.20.9569
中图分类号
O [数理科学和化学]; P [天文学、地球科学]; Q [生物科学]; N [自然科学总论];
学科分类号
07 ; 0710 ; 09 ;
摘要
Sensory neurons of frog dorsal root ganglia (DRG) express at least two subtypes of voltage-gated Na channel and at least two subtypes of voltage-gated K channel. The Na channel subtypes have different sensitivities to tetrodotoxin (TTX) and different kinetics. The TTX-sensitive (TTX-s) Na channel inactivates rapidly and is blocked by nanomolar TTX. The TTX-insensitive (TTX-i) Na channel resists blockage by up to 100 muM TTX (it is blocked by saxitoxin) and inactivates 2-6 times more slowly. The two subtypes of voltage-gated K channel differ in activation kinetics: the fast subtype activates 2-8 times faster than the slow subtype. These Na and K channel subtypes are distributed differentially by cell size, failing into three major groups: (i) small cells with slowly activating K channels and a mixture of TTX-s and TTX-i Na channels; (ii) small cells with slowly activating K channels and TTX-s Na channels; and (iii) large cells with rapidly activating K channels and TTX-s Na channels. The contributions of these channel subtypes to the electrical properties of sensory neurons were investigated under conditions that minimized the contribution of Ca current. Under these conditions, action potential duration is correlated with the channel subtypes expressed: cells with both TTX-i and TTX-s Na channels and slowly activating K channels exhibit long-duration action potentials, cells with TTX-s Na channels and slowly activating K channels exhibit intermediate-duration action potentials, and cells with TTX-s Na channels and rapidly activating K channels exhibit short-duration action potentials.
引用
收藏
页码:9569 / 9573
页数:5
相关论文
共 36 条
[1]  
Almers W, 1978, Rev Physiol Biochem Pharmacol, V82, P96, DOI 10.1007/BFb0030498
[2]  
[Anonymous], 1986, NUMERICAL RECIPES
[3]   A QUANTITATIVE STUDY OF POTASSIUM CHANNEL KINETICS IN RAT SKELETAL-MUSCLE FROM 1 TO 37-DEGREES-C [J].
BEAM, KG ;
DONALDSON, PL .
JOURNAL OF GENERAL PHYSIOLOGY, 1983, 81 (04) :485-512
[4]   PATCH-CLAMP STUDY OF THE TETRODOTOXIN-RESISTANT SODIUM CURRENT IN GROUP C SENSORY NEURONS [J].
BOSSU, JL ;
FELTZ, A .
NEUROSCIENCE LETTERS, 1984, 51 (02) :241-246
[5]  
BROWN AM, 1981, J PHYSIOL-LONDON, V318, P479
[6]  
CAMPBELL D T, 1988, Society for Neuroscience Abstracts, V14, P597
[7]  
CAMPBELL DT, 1988, BIOPHYS J, V53, pA15
[8]  
DUBOIS JM, 1981, J PHYSIOL-LONDON, V318, P297
[9]  
ERLANGER J, 1937, ELECTRICAL SIGNS NER
[10]   KINETIC AND PHARMACOLOGICAL PROPERTIES DISTINGUISHING 3 TYPES OF CALCIUM CURRENTS IN CHICK SENSORY NEURONS [J].
FOX, AP ;
NOWYCKY, MC ;
TSIEN, RW .
JOURNAL OF PHYSIOLOGY-LONDON, 1987, 394 :149-172