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Titolo:
5-HYDROXYTRYPTAMINE RESPONSES IN IMMATURE RAT ROSTRAL VENTROLATERAL MEDULLA NEURONS IN-VITRO
Autore:
HWANG LL; DUN NJ;
Indirizzi:
E TENNESSEE STATE UNIV,JAMES H QUILLEN COLL MED,DEPT PHARMACOL,POB 70577 JOHNSON CITY TN 37614 MED COLL OHIO,DEPT ANAT & NEUROBIOL TOLEDO OH 43614
Titolo Testata:
Journal of neurophysiology
fascicolo: 3, volume: 80, anno: 1998,
pagine: 1033 - 1041
SICI:
0022-3077(1998)80:3<1033:5RIIRR>2.0.ZU;2-C
Fonte:
ISI
Lingua:
ENG
Soggetto:
CENTRAL NERVOUS-SYSTEM; DORSAL RAPHE NEURONS; SEROTONIN RECEPTORS; BINDING-SITES; ADULT-RAT; INVITRO; CURRENTS; NUCLEUS; BRAIN; 5-HT;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Science Citation Index Expanded
Citazioni:
40
Recensione:
Indirizzi per estratti:
Citazione:
L.L. Hwang e N.J. Dun, "5-HYDROXYTRYPTAMINE RESPONSES IN IMMATURE RAT ROSTRAL VENTROLATERAL MEDULLA NEURONS IN-VITRO", Journal of neurophysiology, 80(3), 1998, pp. 1033-1041

Abstract

Whole cell patch recordings were made from rostral ventrolateral medulla (RVLM) neurons of brainstem slices from 8- to 12-day-old rats. By superfusion or pressure ejection to RVLM neurons, 5-hydroxytryptamine (5-HT) elicited three types of membrane potential changes: a slow hyperpolarization (5-HTH), a slow depolarization (5-HTD) and a biphasic response, which persisted in a tetrodotoxin (TTX, 0.3 mu M)-containing solution. 5-HTH were accompanied by a decrease of input resistance in the majority of responsive neurons. Hyperpolarization reduced and depolarization increased the 5-HTH; the mean reversal potential was -92.3 mV in 3.1 mM and shifted to -69.3 mV in 7 mM [K+](o). Barium (Ba2+, 0.1mM) but not tetraethylammonium (TEA, 10 mM) suppressed 5-HTH. The 5-HT1A receptor agonist (+/-)-8-hydroxy-dipropylamino-tetralin (8-OH-DPAT; 5-50 mu M) hyperpolarized RVLM neurons. The 5-HT1A antagonist pindobind-5-HT1A (PBD; 1-3 mu M) and the 5-HT2/5-HT1 receptor antagonist spiperone (1-10 mu M) suppressed 5-HTH and the hyperpolarizing phase of biphasic responses; the 5-HT2 receptor antagonist ketanserin (3 mu M) was without significant effect. 5-HTD were associated with an increase or no apparent change of input resistance in RVLM neurons. Hyperpolarization of the membrane decreased or caused no apparent change in 5-HTD. 5-HTD were reduced in an elevated [K+](o) (7.0 mM) solution and >60%in a low Na+ (26 mM) solution and were not significantly changed in alow Cl- (6.7 mM) or Ca2+-free/high Mg2+ (10.9 mM) solution. The 5-HT2receptor agonist alpha-methyl-5-HT (50 mu M) depolarized RVLM neurons, and the 5-HT2 antagonist ketanserin (1-10 mu M) attenuated the 5-HTDand the depolarizing phase of biphasic responses: whereas the 5-HT1A receptor antagonist PBD (2 mu M) was without effect. Inclusion of the hydrolysis resistant guanine nucleotide GDP-beta-S in patch solution significantly reduced the 5-HTH as well as the 5-HTD. The present studyshows that, in the immature rat RVLM neurons, 5-HT causes a slow hyperpolarization and depolarization probably by interacting with 5-HT1A and 5-HT2 receptors, which are G-proteins coupled. 5-HTH may involve anincrease of an inwardly rectifying K+ conductance, and 5-HTD appear to be caused by a decrease of K+ conductance and/or increase of nonselective cation conductance.

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Documento generato il 30/03/20 alle ore 18:57:09