Effects of chronic Inflammatory pain on development of learning and memory and proenkephalin mRNA expression in hippocampus of neonatal rats
- VernacularTitle:慢性炎性疼痛对新生大鼠学习记忆功能发育及海马前脑啡肽mRNA表达的影响
- Author:
Shuling PENG
;
Yujuan LI
;
Chaoquan WAN
- Publication Type:Journal Article
- Keywords:
Pain;
Chronic disease;
Hippocampus;
Learning;
Memory;
Enkephalins;
RNA,messenger
- From:
Chinese Journal of Anesthesiology
1996;0(08):-
- CountryChina
- Language:Chinese
-
Abstract:
Objective To investigate the effects of chronic inflammatory pain induced by injection of complete Freund' s adjuvant (CFA) into the plantar surface of hindpaw on the development of learning and memory and proenkephalin mRNA expression in hippocampus of neonatal rats. Methods sixty neonatal SD rats (6 rats from each of 10 litters) were randomly divided into control and chronic pain group ( n = 30; 3 rats from each of the 10 litters). In chronic pain group CFA 20 ? l was injected subcutaneously into plantar surface of left hindpaw on the 2nd day after birth whereas in control group normal saline 20 ? l was injected instead of CFA. Ten animals (1 rat from each of the 10 litters) in each group were killed on the 10th and 21st day after birth respectively. Hippocampi were removed for determination of proenkephalin mRNA expression by RT-PCR. Ten animals (1 rat from each of the 10 litters) in each group underwent Morris water maze test 3 times a day for 8 days starting from the 21st day after birth. Results The mean latent period before the rats found the hidden platform was significantly longer in chronic pain group than in control group. When the platform was removed the swimming time and distance of the rats in chronic pain group were significantly shorter than those in control group. There was no significant difference in the latent period before the rats found the visible platform between the two groups. The proenkephalin mRNA expression in hippocampus on the 10th and 21st day after birth was significantly lower in chronic pain group than in control group ( P
