Effects of morphine and tramadol pre-emptive employment on expressions of substance P and calcitonin gene-related peptide mRNA in dorsal root ganglia following acute myocardial ischemia in rats / 中华急诊医学杂志

ABSTRACT

Objective To investigate the effects of morphine and tramadol pre-emptive use on the expressions of substance P mRNA (SPmRNA) and calcitonin gene-related peptide mRNA (CGRPmRNA) in dorsal root ganglia (DRG) following acute myocardial ischemia in the rats. Method Twenty-four adult male SD rats weighing 270 to 300 g were randomly (random number) divided into four groups (n = 6, in each) group Ⅰ(sham operation), group Ⅱ (myocardial ischemia), group Ⅲ (morphine pre-emptive use) and group Ⅳ (tramadol pre-emptive use). The left anterior descending branch of coronary artery was occluded (CAO) for 3 hours in rats of group Ⅱ and Ⅳ.In group Ⅲ morphine 1.25 mg·kg-1 was injected through caudal vein 15 minutes before CAO.In group Ⅳ,tramadol 12.5 mg·kg-1 was daministered via caudal vein 15 minutes before CAO.In 3 hours after myocardial ischemia, the tissue of DRG (T1-5) were taken for detecting the expressions of SPmRNA and CGRPmRNA by using RT-PCR. One-way ANOVA was used for statistical analysis. Results In the tissue of DRG, the expressions of SPmRNA(0.93±0.02) ,α-CGRP mRNA(0.98±0.02) and β-CGRP mRNA(0.83 ± 0.02)were up-regulated in group Ⅱ compared with those in group Ⅰ (0.84±0.04),(0.86±0.01),(0.45±0.03) (P ＜0.05),and decreased markedly in group Ⅲ (0.88 ± 0.03) ,(0.90 ± 0.02), (0.67 ± 0.02) (P ＜ 0.05) and group Ⅳ (0.88±0.04) ,(0.90 ± 0.01),(0.66±0.01) (P ＜ 0.05), but showed no difference between group Ⅲ and Ⅳ (P ＞ 0.05). Conclusions Morphine and tramadol pre-emptive use can significantly inhibit the expressions of SPmRNA and CGRPmRNA in rat's dorsal root ganglia after CAO.