Sweet taste transduction in hamster: Sweeteners and cyclic nucleotides depolarize taste cells by reducing a K+ current

被引:69
作者
Cummings, TA
Daniels, C
Kinnamon, SC
机构
[1] COLORADO STATE UNIV, DEPT ANAT & NEUROBIOL, FT COLLINS, CO 80523 USA
[2] UNIV COLORADO, HLTH SCI CTR, ROCKY MT TASTE & SMELL CTR, DENVER, CO 80262 USA
关键词
D O I
10.1152/jn.1996.75.3.1256
中图分类号
Q189 [神经科学];
学科分类号
071006 ;
摘要
1. The gigaseal voltage-clamp technique was used to record responses of hamster taste receptor cells to synthetic sweeteners and cyclic nucleotides. Voltage-dependent currents and steady-state currents were monitored during bath exchanges of saccharin, two high-potency sweeteners, 8-chlorophenylthio-adenosine 3',5'-cyclic monophosphate (8cpt-cAMP), and dibutyryl-guanosine 3',5'-cyclic monophosphate (db-cGMP). 2. Of the 237 fungiform taste cells studied, only one in eight was sweet responsive. Outward currents, both voltage-dependent and resting, were reduced by all of the sweeteners tested in sweet-responsive taste cells, whereas these currents were unaffected by sweeteners in sweet-unresponsive taste cells. 3. In every sweet-responsive cell tested, 8cpt-cAMP and db-cGMP mimicked the response to the sweeteners, but neither nucleotide elicited responses in sweet-unresponsive cells. Thus there was a one-to-one correlation between sweet responsivity and cyclic nucleotide responsivity. 4. Sweet responses showed cross adaptation with cyclic nucleotide responses. This indicates that the same ion channel is modulated by sweeteners and cyclic nucleotides. 5. The sweetener- and cyclic nucleotide-blocked current had an apparent reversal potential of -50 mV, which was dose to the potassium reversal potential in these experiments. In addition, there was no effect of sweeteners and cyclic nucleotides in the presence of the K+ channel blocker tetraethylammonium bromide (TEA). These data suggest that block of a resting, TEA-sensitive K+ current is the final common step Lading to taste cell depolarization during sweet transduction. 6. These data, together with data from a previous study (Cummings et al. 1993), suggest that both synthetic sweeteners and sucrose utilize second-messenger pathways that block a resting K+ conductance to depolarize the taste cell membrane.
引用
收藏
页码:1256 / 1263
页数:8
相关论文
共 37 条
[1]   PATCH-CLAMP STUDY OF ISOLATED TASTE RECEPTOR-CELLS OF THE FROG [J].
AVENET, P ;
LINDEMANN, B .
JOURNAL OF MEMBRANE BIOLOGY, 1987, 97 (03) :223-240
[2]   TRANSDUCTION IN TASTE RECEPTOR-CELLS REQUIRES CAMP-DEPENDENT PROTEIN-KINASE [J].
AVENET, P ;
HOFMANN, F ;
LINDEMANN, B .
NATURE, 1988, 331 (6154) :351-354
[3]   MEMBRANE CURRENTS IN TASTE CELLS OF THE RAT FUNGIFORM PAPILLA - EVIDENCE FOR 2 TYPES OF CA CURRENTS AND INHIBITION OF K-CURRENTS BY SACCHARIN [J].
BEHE, P ;
DESIMONE, JA ;
AVENET, P ;
LINDEMANN, B .
JOURNAL OF GENERAL PHYSIOLOGY, 1990, 96 (05) :1061-1084
[4]  
BERNHARDT SJ, 1995, CHEM SENSES, V20, P122
[5]  
BERNHARDT SJ, 1995, CHEM SENSES, V20, P121
[6]   BIOCHEMICAL STUDIES OF TASTE SENSATION .2. LABELING OF CYCLIC-AMP OF BOVINE TASTE PAPILLAE IN RESPONSE TO SWEET AND BITTER STIMULI [J].
CAGAN, RH .
JOURNAL OF NEUROSCIENCE RESEARCH, 1976, 2 (5-6) :363-371
[7]  
CUMMINGS T A, 1991, Chemical Senses, V16, P511
[8]   SWEET TASTE TRANSDUCTION IN HAMSTER TASTE CELLS - EVIDENCE FOR THE ROLE OF CYCLIC-NUCLEOTIDES [J].
CUMMINGS, TA ;
POWELL, J ;
KINNAMON, SC .
JOURNAL OF NEUROPHYSIOLOGY, 1993, 70 (06) :2326-2336
[9]   APICAL K+ CHANNELS IN NECTURUS TASTE CELLS - MODULATION BY INTRACELLULAR FACTORS AND TASTE STIMULI [J].
CUMMINGS, TA ;
KINNAMON, SC .
JOURNAL OF GENERAL PHYSIOLOGY, 1992, 99 (04) :591-613
[10]  
CUMMINGS TA, 1991, BIOPHYS J, V59, pA549