Catalogo Articoli (Spogli Riviste)

OPAC HELP

Titolo:
STRYCHNINE - A POTENT COMPETITIVE ANTAGONIST OF ALPHA-BUNGAROTOXIN-SENSITIVE NICOTINIC ACETYLCHOLINE-RECEPTORS IN RAT HIPPOCAMPAL-NEURONS
Autore:
MATSUBAYASHI H; ALKONDON M; PEREIRA EFR; SWANSON KL; ALBUQUERQUE EX;
Indirizzi:
UNIV MARYLAND,SCH MED,DEPT PHARMACOL & EXPT THERAPEUT,655 W BALTIMOREST BALTIMORE MD 21201 UNIV MARYLAND,SCH MED,DEPT PHARMACOL & EXPT THERAPEUT BALTIMORE MD 21201 UNIV FED RIO DE JANEIRO,INST BIOMED SCI,DEPT CLIN & BASIC PHARMACOL BR-21944 RIO JANEIRO BRAZIL
Titolo Testata:
The Journal of pharmacology and experimental therapeutics
fascicolo: 3, volume: 284, anno: 1998,
pagine: 904 - 913
SICI:
0022-3565(1998)284:3<904:S-APCA>2.0.ZU;2-Y
Fonte:
ISI
Lingua:
ENG
Soggetto:
GATED ION CHANNELS; OUTER HAIR-CELLS; GLYCINE RECEPTOR; PHARMACOLOGICAL PROPERTIES; BINDING-SITES; SPINAL-CORD; AMINO-ACID; DIVERSITY; BLOCKADE; CURRENTS;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
52
Recensione:
Indirizzi per estratti:
Citazione:
H. Matsubayashi et al., "STRYCHNINE - A POTENT COMPETITIVE ANTAGONIST OF ALPHA-BUNGAROTOXIN-SENSITIVE NICOTINIC ACETYLCHOLINE-RECEPTORS IN RAT HIPPOCAMPAL-NEURONS", The Journal of pharmacology and experimental therapeutics, 284(3), 1998, pp. 904-913

Abstract

In our study, evidence is provided that strychnine, a competitive antagonist at glycine-gated Cl- channels, is also a potent competitive antagonist at native alpha-7-containing, alpha-bungarotoxin-sensitive nicotinic acetylcholine receptor (nAChRs). To address the effects of strychnine on two types of nicotinic responses, the whole-cell mode of the patch-clamp technique was applied to rat hippocampal neurons in culture. Type IA and type II nicotinic currents evoked by acetylcholine (ACh) were inhibited by strychnine in a concentration-dependent manner with IC(50)s of 1.2 and 38 mu M, respectively. Strychnine (2 mu M) decreased the peak amplitude of the alpha-bungarotoxin-sensitive type IA current in a voltage-independent manner and prolonged the decay phase of this current. The concentration-response curve for ACh in evoking type IA current showed a parallel shift to the right in the presence of strychnine (2 mu M); the EC50 for ACh was increased from 0.4 to 0.8 mM. These findings suggest that strychnine acts as a competitive antagonist of ACh at the alpha 7 nAChRs that subserve type IA current. In contrast, the inhibition by strychnine of type II current was strongly voltage dependent, and the decay phase of this current was markedly accelerated by the toxin, suggesting an open-channel blockade by strychnine of the alpha 4 beta 2 nAChRs subserving type II currents. Preexposure of the neurons to strychnine enhanced its ability to decrease the peak amplitude of type II currents, indicating that the toxin may also act on alpha 4 beta 2 nAChR channels that are not open. It is concludedthat strychnine is a potent competitive antagonist of ACh at neuronalalpha 7 nAChRs and a noncompetitive antagonist at the alpha 4 beta 2 nAChR.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 28/03/20 alle ore 10:25:55