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Titolo:
Ventrolateral periaqueductal gray matter and the control of tonic immobility
Autore:
Monassi, CR; Leite-Panissi, CRA; Menescal-De-Oliveira, L;
Indirizzi:
Univ Sao Paulo, Fac Med Ribeirao Preto, Dept Physiol, BR-14049900 RibeiraoPreto, SP, Brazil Univ Sao Paulo Ribeirao Preto SP Brazil BR-14049900 BCaoPreto, SP, Brazil
Titolo Testata:
BRAIN RESEARCH BULLETIN
fascicolo: 3, volume: 50, anno: 1999,
pagine: 201 - 208
SICI:
0361-9230(199910)50:3<201:VPGMAT>2.0.ZU;2-8
Fonte:
ISI
Lingua:
ENG
Soggetto:
PHASEOLUS-VULGARIS-LEUKOAGGLUTININ; AMINO-ACID MICROINJECTION; EFFERENT PROJECTIONS; PARABRACHIAL REGION; BRAIN-STEM; IMMUNOREACTIVE NEURONS; QUANTITATIVE LIGHT; MIDBRAIN CONTROL; PAIN MODULATION; RAPHE MAGNUS;
Keywords:
periaqueductal gray matter; tonic immobility; defensive behavior; guinea pig;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
61
Recensione:
Indirizzi per estratti:
Indirizzo: Menescal-De-Oliveira, L Univ Sao Paulo, Fac Med Ribeirao Preto, Dept Physiol, BR-14049900 RibeiraoPreto, SP, Brazil Univ Sao Paulo Ribeirao Preto SPBrazil BR-14049900 BC
Citazione:
C.R. Monassi et al., "Ventrolateral periaqueductal gray matter and the control of tonic immobility", BRAIN RES B, 50(3), 1999, pp. 201-208

Abstract

Tonic immobility is an inborn defensive behavior characterized by a temporary state of profound and reversible motor inhibition elicited by some forms of physical restraint. The periaqueductal gray matter (PAG) contains neural circuits involved in descending pain modulation, as well as in the modulation of Tl. We have reported previously that the cholinergic stimulation of the ventrolateral PAG increases the duration of Tl in guinea pigs. In thepresent study, we attempted to characterize further the modulation of Tl by pharmacological alteration of the neurochemistry of the ventrolateral PAGcircuitry. We observed that both cholinergic (carbachol, 5.4 nmol/0.2 mu l) and opioidergic stimulations (morphine, 4.48 nmol/0.2 mu l) of the ventrolateral PAG increase the duration of Tl and that these effects can be reversed by pre-treatment with naloxone (2.74 nmol/0.2 mu l). Our results also showed that microinjection of the GABAergic agonist muscimol (1, 0.5, and 0.26 nmol/0.2 mu l) decreased the duration of Tl episodes, while microinjection of the GABAergic antagonist bicuculline (1 nmol/mu l) increased it. Moreover, we observed that preadministration of muscimol (0.13 nmol/0.2 mu l) at a dose that had no effect per se at this site antagonized the potentiating effect of morphine. Our results suggest that this modulation of Tl from the ventrolateral PAG circuitry is accomplished by a complex interaction of cholinergic, opioidergic, and GABAergic mechanisms, similar to that proposed for descending antinociceptive circuits. (C) 1999 Elsevier Science Inc.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 11/07/20 alle ore 17:28:47