Catalogo Articoli (Spogli Riviste)

OPAC HELP

Titolo:
MULTIPLE EFFECTS OF SEROTONIN ON MEMBRANE-PROPERTIES OF TRIGEMINAL MOTONEURONS IN-VITRO
Autore:
HSIAO CF; TRUEBLOOD PR; LEVINE MS; CHANDLER SH;
Indirizzi:
UNIV CALIF LOS ANGELES,DEPT PHYSIOL SCI,2851 SLICHTER HALL LOS ANGELES CA 90095 UNIV CALIF LOS ANGELES,DEPT PHYSIOL SCI LOS ANGELES CA 90095 UNIV CALIF LOS ANGELES,MENTAL RETARDAT RES CTR LOS ANGELES CA 90095
Titolo Testata:
Journal of neurophysiology
fascicolo: 6, volume: 77, anno: 1997,
pagine: 2910 - 2924
SICI:
0022-3077(1997)77:6<2910:MEOSOM>2.0.ZU;2-M
Fonte:
ISI
Lingua:
ENG
Soggetto:
RHYTHMICAL JAW MOVEMENTS; LOCUS-CERULEUS NEURONS; RAT SPINAL MOTONEURONS; CATIONIC CURRENT IH; GUINEA-PIG; FACIAL MOTONEURONS; IN-VITRO; INTRACELLULAR ANALYSIS; POTASSIUM CONDUCTANCE; ELECTRICAL GEOMETRY;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Science Citation Index Expanded
Citazioni:
57
Recensione:
Indirizzi per estratti:
Citazione:
C.F. Hsiao et al., "MULTIPLE EFFECTS OF SEROTONIN ON MEMBRANE-PROPERTIES OF TRIGEMINAL MOTONEURONS IN-VITRO", Journal of neurophysiology, 77(6), 1997, pp. 2910-2924

Abstract

Intracellular recordings from guinea pig trigeminal motoneurons (TMNs) in brain stem slices were used to determine the underlying ionic mechanisms responsible for our previously demonstrated enhancement of TMNexcitability during jaw movements by serotonin (5-HT). 5-HT (0.5-100 mu M) depolarized motoneurons and increased input resistance in the majority of neurons tested. Additionally, 5-HT reduced the amplitude of the postspike medium-duration afterhyperpolarization, decreased the current threshold for maintained spike discharge, and increased the maximum slope of the steady-state spike frequency-current relationship. Under voltage clamp, from holding potentials close to resting potential,5-HT produced an inward current and a decrease in instantaneous slopeconductance, suggesting a reduction In a resting K+ leak conductance (I-leak). The instantaneous current-voltage(I-V) relationship for the inward 5-HT current (I5-HT) was linear throughout most of the voltage range tested. However, the steady-state I-V relationship showed some degree of inward rectification at potentials starting around -70 mV. The mean reversal potential for the instantaneous 1(5-HT) was -86.2 +/- 4.5 (SE) mV (n = 9), a value slightly negative to the predicted potassium equilibrium potential of -82 mV in these neurons. In the presence of 2 mM Ba2+, 5-HT application did nor produce a further reduction in input conductance, but did expose a Ba2+-insensitive residual inward current that was resistant to Cs+ application. The instantaneous I-V relationship during 5-HT application in the presence of Ba2+ was shifteddownward and parallel to control, suggesting that Ba2+ and 5-HT blockthe same resting I-leak. The residual Ba2+- and Cs+-insensitive component of the total inward I5-HT was voltage independent and was blockedwhen the extracellular Na+ was replaced by choline, suggesting that the predominant charge carrier for this residual current is Na+. 5-HT enhanced a hyperpolarization-activated cationic current, I-h. In the presence of Ba2+, the time course of 1(5-HT) resembled that of I-h and showed a similar voltage dependence that was blocked by extracellular Cs+ (1-3 mM). The effects of 5-HT on membrane potential, input resistance, and I-h were partially mimicked by 5-HT2 agonists and suppressed by 5-HT2 antagonists. It is concluded that 5-HT enhances TMN membrane excitability through modulation of multiple intrinsic membrane conductances. This provides for a mechanism(s) to fine tune the input-output discharge properties of these neurons, thus providing them with greaterflexibility in output in response to time-varying synaptic inputs during various movements of the jaw.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 25/11/20 alle ore 18:58:02