Brain noradrenergic systems modulate the ceco-colonic myoelectric activity in rats.
The role of the brain noradrenergic systems in the control of the ceco-colonic myoelectric activity was investigated in rats following lesions with intracerebroventricular (icv) or intracisternal (ic) injection of 6-hydroxydopamine (6-OHDA). Controls received the vehicle alone. The ceco-colonic myoelectric activity was recorded 3 weeks later in conscious rats chronically fitted with electrodes. After icv injection of 6-OHDA, lesions of rostral and caudal (spinal) noradrenergic systems were observed whereas only spinal noradrenergic systems were lesioned after ic injection. This differential pattern of lesions was followed by a differential pattern of ceco-colonic myoelectric activity. In fasted animals, a significant increase of the long spike burst (LSB) frequency (nb min-1) was observed after icv injection of 6-OHDA whereas no modification was observed after ic injection of the neurotoxic. After a 6-g pelleted rat diet, a significant increase of the LSB frequency was also observed in the icv lesioned group when compared to controls. No modification of the ceco-colonic noradrenergic innervation was observed, thus confirming the central selectivity of these lesions. Lesions of central noradrenergic systems modify the LSB frequency in rats; the rostral noradrenergic systems seem to play the major role.
Bonaz
B
B
Laboratoire de Physiologie, Institut National de la Santé et de la Recherche Médicale, U318, Hôpital A. Michallon, Centre Hospitalier Universitaire, Grenoble, France.
Martin
L
L
Beurriand
E
E
Hostein
J
J
Feuerstein
C
C
D000818:Animals; D001921:Brain / Q000502:physiology*; D001923:Brain Chemistry / Q000502:physiology; D002432:Cecum / Q000294:innervation / Q000378:metabolism / Q000502:physiology*; D002946:Cisterna Magna; D003106:Colon / Q000294:innervation / Q000378:metabolism / Q000502:physiology*; D007150:Immunohistochemistry; D007267:Injections; D007276:Injections, Intraventricular; D008297:Male; D016065:Myoelectric Complex, Migrating / Q000502:physiology*; D009638:Norepinephrine / Q000378:metabolism / Q000502:physiology*; D016627:Oxidopamine / Q000008:administration & dosage; D051381:Rats; D017208:Rats, Wistar; D013116:Spinal Cord / Q000502:physiology; D013563:Sympathectomy, Chemical; D013564:Sympathetic Nervous System / Q000378:metabolism / Q000502:physiology*
D016627:Oxidopamine; D009638:Norepinephrine