Volume 4, Issue 2 (Fall and Winter 2000)                   Physiol Pharmacol 2000, 4(2): 213-218 | Back to browse issues page

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Nikbakht F, Behzadi Z. Evaluation of specific lesion of ventrolateral PAG projecting to NRM by ibotenic acid using formalin test. Physiol Pharmacol. 2000; 4 (2) :213-218
URL: http://ppj.phypha.ir/article-1-217-en.html
Abstract:   (13677 Views)
It has been reported that neurons in the VL PAG projecting to nucleus raphe magnus (NRM) utilize excitatory amino acids as neurotransmitter. This projection plays an important role in the descending pain modulatory system. In order to determine the role of this pathway in pain perception, male rats received unilateral injection of ibotenic acid stereotaxically. For lesioning VL PAG, unilateral injection of ibotenic acid (0.2 and 0.5 µl) (a specific neurotoxin for EAA-containing neurons) was made. After a week recovery period, the nociception was evaluated using formalin test for a period of 60 min. At the end of experiments, animals were perfused by formaldehyde 10%. Serial sections (80 µm) wee prepared using vibratome. The sections were then Nissl stained and examined to determine the lesion location. The results revealed a significant increase in the first phase of formalin test. However, in the second phase, only 0.5 µl of the neurotoxin caused a significant decrease in pain perception. It is concluded that NMDA receptors within the PAG are involved in the perception of pain as measured in the formalin test.
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Types of Manuscript: Original Research | Subject: Nervous system (others)