Depending on the mode of application morphine enhances or depresses somatocardiac sympathetic A- and C-reflexes in anesthetized rats.
Neurosci Res
; 15(4): 281-8, 1992 Dec.
Article
em En
| MEDLINE
| ID: mdl-1337580
ABSTRACT
The effects of morphine on the reflex discharges in sympathetic efferents recorded from branches of the inferior cardiac nerve (ICN) were studied in rats anesthetized with alpha-chloralose and urethane. Somatocardiac sympathetic A- and C-reflexes were elicited by single shock electrical stimulation of myelinated (A) and unmyelinated (C) afferent fibers of the tibial nerve, respectively. Application of morphine either into the femoral vein or into the subarachnoid space of the cisterna magna enhanced both the A- and C-reflexes in a dose-dependent manner, while application of morphine into the intrathecal space of the lumbar spinal cord selectively inhibited C-reflexes. All effects of morphine were antagonized by naloxone. Application of morphine via the internal carotid artery to central nervous structures above the brainstem had no effect on the somatocardiac sympathetic reflexes. It is concluded that in the anesthetized rat morphine in a dose-dependent and naloxone-reversible manner (1) depresses spinal transmission of C-afferent activity, whereas (2) at the brainstem it enhances the transmission of somatocardiac sympathetic A- and C-reflexes.
Buscar no Google
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Reflexo
/
Sistema Nervoso Simpático
/
Coração
/
Morfina
Limite:
Animals
Idioma:
En
Revista:
Neurosci Res
Assunto da revista:
NEUROLOGIA
Ano de publicação:
1992
Tipo de documento:
Article
País de afiliação:
Japão