[ effect of electrical lesion of paragigantocellularis lateralis nucleus on acute pain perception in presence of clonidine [alpha2 adrenergic agonist] in rat]

ABSTRACT

Paragigantocellularis lateralis nucleus [LPGi] involves several functions such as cardiovascular regulation, sexual behavior, withdrawal syndrome and pain. Ln addition, the role of a2 adrenergic in analgesia has been reported as well. We studied the role of a2 adrenergic receptor in LPGi on acute pain. After surgical process LPGi was lesioned bilaterally by using electrical DC current [1mA, 6 second], at stereotaxic coordinates of [AP=11.8, Lat.+/-l.86 and Depth=10.5]. Pain perception was tested using a standard hot plate. No significant difference was found between the control group and the sham group. There is a significant difference between the sham group and lesion+saline group [P<0.0002]. There are significant differences between the lesion+saline group and lesion+0.02 mg/km clonidine [P<0.001] as well as lesion+saline group and lesion+0.2 mg/km clonidine [P<0.001]. We conclude that a2 adrenergic receptors of LPGi nucleus not only have a major role in the clonidine induced analgesia but also may be affecting other parts of CNS to induce analgesia in rat