The reduction of antinociceptive effect of morphine administered intraventricularly is correlated with the decrease of serotonin release from the spinal cord in streptozotocin-induced diabetic rats.
1. The antinociceptive effect of morphine (25 micrograms) administered into the 3rd ventricle was significantly attenuated in streptozotocin-induced diabetic rats as measured by the tail-flick assay. 2. The release of serotonin (5-HT; 5-hydroxytryptamine) from the spinal cord caused by intraventricular injection of morphine (25 micrograms) was significantly reduced in streptozotocin-induced diabetic rats. 3. No differences of 5-HT contents of the spinal cord (lumbar cord) between streptozotocin-induced diabetic- and vehicle-treated rats were found. 4. It is concluded that the reduction of antinociception produced by intraventricular injection of morphine in streptozotocin-induced diabetic rats might be, at least partly, due to the decrease of 5-HT release from the spinal cord.
Suh
H W
HW
Department of Pharmacology, College of Medicine, Hallym University, Chunchon, Kwangwon-Do, S. Korea.
Song
D K
DK
Wie
M B
MB
Jung
J S
JS
Hong
H E
HE
Choi
S R
SR
Kim
Y H
YH
D000701:Analgesics, Opioid / Q000008:administration & dosage / Q000494:pharmacology*; D000818:Animals; D002851:Chromatography, High Pressure Liquid; D003921:Diabetes Mellitus, Experimental / Q000378:metabolism* / Q000503:physiopathology*; D006897:Hydroxyindoleacetic Acid / Q000378:metabolism; D007276:Injections, Intraventricular; D008297:Male; D009020:Morphine / Q000008:administration & dosage / Q000494:pharmacology*; D010147:Pain Measurement / Q000187:drug effects; D051381:Rats; D017207:Rats, Sprague-Dawley; D011930:Reaction Time / Q000187:drug effects; D012701:Serotonin / Q000378:metabolism*; D013116:Spinal Cord / Q000378:metabolism*
D000701:Analgesics, Opioid; D012701:Serotonin; D006897:Hydroxyindoleacetic Acid; D009020:Morphine