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Titolo:
Gustatory neuron types in rat geniculate ganglion
Autore:
Lundy, RF; Contreras, RJ;
Indirizzi:
Florida State Univ, Dept Psychol, Tallahassee, FL 32306 USA Florida State Univ Tallahassee FL USA 32306 ol, Tallahassee, FL 32306 USA
Titolo Testata:
JOURNAL OF NEUROPHYSIOLOGY
fascicolo: 6, volume: 82, anno: 1999,
pagine: 2970 - 2988
SICI:
0022-3077(199912)82:6<2970:GNTIRG>2.0.ZU;2-U
Fonte:
ISI
Lingua:
ENG
Soggetto:
SINGLE CHORDA TYMPANI; TASTE NERVE RESPONSES; GLOSSOPHARYNGEAL NERVE; AMILORIDE INHIBITION; MACACA-MULATTA; BRAIN-STEM; HAMSTER; FIBERS; TRANSPORT; MONKEY;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
58
Recensione:
Indirizzi per estratti:
Indirizzo: Contreras, RJ Penn State Coll Med, Dept Behav Sci, H181, Hershey, PA 17033USA Penn State Coll Med H181 Hershey PA USA 17033 , PA 17033 USA
Citazione:
R.F. Lundy e R.J. Contreras, "Gustatory neuron types in rat geniculate ganglion", J NEUROPHYS, 82(6), 1999, pp. 2970-2988

Abstract

We used extracellular single-cell recording procedures to characterize thechemical and thermal sensitivity of the rat geniculate ganglion to lingualstimulation, and to examine the effects of specific ion transport antagonists on salt transduction mechanisms. Hierarchical cluster analysis of the responses from 73 single neurons to 3 salts (0.075 and 0.3 M NaCl, KCI, and NH, Cl), 0.5 M sucrose, 0.01 M HCl, and 0.02 M quinine HCl (QHCl) indicated3 main groups that responded best to either sucrose, HCl, or NaCl. Eight narrowly tuned neurons were deemed sucrose-specialists and 33 broadly tuned neurons as HCl-generalists. The NaCl group contained three identifiable subclusters: 18 NaCl-specialists, 11 NaCl-generalists, and 3 QHCl-generalists. Sucrose- and NaCl-specialists responded specifically to sucrose and NaCl, respectively. All generalist neurons responded to salt, acid, and alkaloid stimuli to varying degree and order depending on neuron type. Response order was NaCl > HCl = QHCl > sucrose in NaCl-generalists, HCl > NaCl > QHCl > sucrose in HCl-generalists, and QHCl = NaCl = HCl > sucrose in QHCl-generalists. NaCl-specialists responded robustly to low and high NaCl concentrations, but weakly, if at all, to high KCl and NH, Cl concentrations after prolonged stimulation. HCl-generalist neurons responded to all three salts, butat twice the rate to NH, Cl than to NaCl and KCI. NaCl- and QHCl-generalists responded equally to the three salts. Amiloride and 5-(N,N-dimethyl)-amiloride (DMA), antagonists of Na+ channels and Na+/H+ exchangers, respectively, inhibited the responses to 0.075 M NaCl only in NaCl-specialist neurons. The K+ channel antagonist, LF-aminopyridine (4-AP), was without a suppressive effect on salt responses, but, when applied alone in solution, it evoked a response in many HCl-generalists and one QHCl-generalist neuron so tested. Of the 39 neurons tested for their sensitivity to temperature, 23 responded to cooling and chemical stimulation, and 20 of these neurons were HCl-generalists. Moreover, the responses to the four standard stimuli were reduced progressively at lower temperatures in HCl- and QHCl-generalist neurons, but not in NaCl-specialists. Thus sodium channels and Na+/H+ exchangers appear to be expressed exclusively on the membranes of receptor cells that synapse with NaCl-specialist neurons. In addition, cooling sensitivity and taste-temperature interactions appear to be prominent features of broadly tuned neuron groups, particularly HCl-generalists. Taken all together, it appears that lingual taste cells make specific connections with afferent fibers that allow gustatory stimuli to be parceled into different input pathways. In,general, these neurons are organized physiologically into specialist and generalist types. The sucrose- and NaCl-specialists alone can provide sufficient information to distinguish sucrose and NaCl from other stimuli, respectively.

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Documento generato il 16/07/20 alle ore 16:43:47