Catalogo Articoli (Spogli Riviste)

OPAC HELP

Titolo:
Late vagal inhibition in neurons of the ventrolateral medulla oblongata inthe rat
Autore:
Zagon, A; Ishizuka, K; Rocha, I; Spyer, KM;
Indirizzi:
Royal Free & Univ Coll Med Sch, Dept Physiol, London NW3 2PF, England Royal Free & Univ Coll Med Sch London England NW3 2PF n NW3 2PF, England
Titolo Testata:
NEUROSCIENCE
fascicolo: 3, volume: 92, anno: 1999,
pagine: 877 - 888
SICI:
0306-4522(1999)92:3<877:LVIINO>2.0.ZU;2-7
Fonte:
ISI
Lingua:
ENG
Soggetto:
BAROSENSITIVE NEURONS; TRACTUS-SOLITARIUS; CONSCIOUS RABBITS; BRAIN-STEM; RECEPTORS; STIMULATION; NUCLEUS; GABA; BARORECEPTOR; MECHANISMS;
Keywords:
IPSP; in vivo intracellular recording; late-onset hyperpolarization; rat; vagus; ventrolateral medulla oblongata;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
42
Recensione:
Indirizzi per estratti:
Indirizzo: Zagon, A Royal Free & Univ Coll Med Sch, Dept Physiol, Royal Free Campus,Rowland Hill St, London NW3 2PF, England Royal Free & Univ Coll Med Sch Royal Free Campus,Rowland Hill St London England NW3 2PF
Citazione:
A. Zagon et al., "Late vagal inhibition in neurons of the ventrolateral medulla oblongata inthe rat", NEUROSCIENC, 92(3), 1999, pp. 877-888

Abstract

Stimulation of cervical vagal afferents elicits long-lasting inhibitory effects in a variety of neuronal populations, although little is known concerning the cellular mechanisms that are involved in these effects. In the present study, the electrophysiological characteristics of responses elicited by cumulative activation of vagal afferents were examined in neurons of therostral ventrolateral medulla oblongata, which play an important role in the coordination of cardiovascular and other Visceral activities. The study has focused on the late-onset, slow inhibitory component of vagal responses, which is likely to affect the temporal modulation of postsynaptic effects. Vagal stimulation elicited four distinct response patterns in intracellularly penetrated neurons (n = 78): excitation, inhibition, excitation-inhibition and inhibition-inhibition. The late inhibitory component was encountered in 43 (55%) of the cells, including five putative medullospinal neurons. It was due to a postsynaptic hyperpolarization which reversed at potentialsmore negative than -83 mV. The voltage dependency, as well as the average onset latency (93 +/- 3.0 ms), duration (270 +/- 16.5 ms) and amplitude (1.3 +/- 0.2 mV as measured at resting membrane potentials), of late inhibition were clearly different from those of the short-latency inhibitory response. The differences in the voltage dependency and time-course of the short-latency responses and the late inhibition indicate that they are mediated bydifferent central relays. In the majority of neurons, late inhibition could be elicited by stimulating only myelinated vagal afferents. The magnitudeof the response was, however, significantly enhanced in 63% of the examined cells when the intensity of stimulation was raised to recruit further myelinated and non-myelinated fibres. This indicates that late vagal inhibition is often elicited by a cumulative activation of convergent afferent inputs. The intracellularly labelled vagally responsive neurons were present at all rostrocaudal levels of the rostral ventrolateral medulla, with an accumulation in the region of the lateral paragigantocellular nucleus. Neurons that exhibited late vagal inhibition were dominant in the juxtafacial regionof this nucleus. Due to its slow time-course, late vagal inhibition may contribute to a tonic modulation of the activity of neurons in the rostral ventrolateral medulla oblongata. It is proposed that late vagal inhibition plays an important role in the temporal integration of sensory inputs in neurons of the rostral ventrolateral medulla oblongata. The time-course and strength of this modulatory effect are related to the level of activity in those Visceral sensory inputs that converge onto the inhibitory interneurons that mediate late inhibition to rostral ventrolateral medulla oblongata neurons. (C) 1999 IBRO. Published by Elsevier Science Ltd.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 26/09/20 alle ore 11:50:12