Involvement of dynorphin A in the inhibition of morphine physical dependence by N-nitro-L-arginine in rats.
- Author:
Xingwang WAN
1
;
Mao HUANG
;
Yaqin HE
;
Wanhai LI
;
Zhendong YOU
;
Changlin LU
Author Information
- Publication Type:Journal Article
- MeSH: Animals; Dose-Response Relationship, Drug; Dynorphins; physiology; Male; Morphine Dependence; prevention & control; Nitroarginine; pharmacokinetics; pharmacology; Rats; Rats, Sprague-Dawley
- From: Chinese Medical Journal 2003;116(7):1055-1058
- CountryChina
- Language:English
-
Abstract:
OBJECTIVETo investigate the involvement of immunoreactive-dynorphin A in the inhibitory effect of N-nitro-L-arginine on the morphine physical dependence in rats.
METHODSThe rats were rendered dependent on morphine by subcutaneous administration of morphine solution three times daily in a manner of dose increment of 5 mg.kg(-1) for 6 days. The degree of morphine physical dependence was monitored by scoring the abstinence syndromes precipitated by 5 mg.kg(-1) naloxone of the rats. The expression levels of immunoreactive dynorphin A in tissues were determined using a radioimmunoassay.
RESULTSIntraperitoneal injection of 5 mg.kg(-1) N-nitro-L-arginine suppresses most of the withdrawal symptoms of morphine dependent rats. N-nitro-L-arginine can elevate the expression of immunoreactive dynorphin.
CONCLUSIONSChronic N-nitro-L-arginine administration can inhibit the development of morphine physical dependence in a manner of dose-dependence, which is significantly related to its role of regulating the endogeneous dynorphin system.
