Phentolamine antagonizes the effects of norepinephrine on the activity of pain-related neurons in the parafascicular nucleus of morphine-dependent rats.
- Author:
Xiu-dong JIN
1
;
Yan-zhong GUAN
;
Shu-jie ZHANG
;
Man-ying XU
;
Wen-jie YUE
Author Information
- Publication Type:Journal Article
- MeSH: Animals; Drug Antagonism; Electrophysiology; Intralaminar Thalamic Nuclei; cytology; drug effects; Neurons; drug effects; Norepinephrine; antagonists & inhibitors; pharmacology; Pain; physiopathology; Phentolamine; pharmacology; Rats; Rats, Wistar
- From: Journal of Southern Medical University 2008;28(2):266-268
- CountryChina
- Language:Chinese
-
Abstract:
OBJECTIVETo examine the antagonization of phentolamine against the effects of norepinephrine (NE) on the activity of pain-related neurons in the parafascicular nucleus of morphine-dependent rats.
METHODSElectric impulses were applied as nociceptive stimulus to the right sciatic nerve of morphine-dependent rats, and the discharges of the pain-related neurons in the parafascicular nucleus were recorded by extracellular recording method with glass microelectrodes.
RESULTSIntracerebroventricular injection of norepinephrine resulted in the inhibition of evoked response of the pain-excited neurons as well as the excitation of evoked response of the pain-inhibiting neurons. Both the inhibitory effect on the electric discharges of the pain-excited neurons and the excitatory effect on the pain-inhibiting neurons of norepinephrine were almost completely blocked by intracerebroventricular administration of phentolamine.
CONCLUSIONPhentolamine antagonizes the inhibitory effect of norepinephrine on the activity of pain-related neurons in the parafascicular nucleus in morphine-dependent rats, and norepinephrine may play an important role in the integration of the pain signal through the alpha-receptors.
