'Medical University Prof. Dr. Paraskev Stoyanov - Varna'
Doi
Abstract
The immunohistochemical localization of cannabinoid type 1 (CB1) receptors in periaqueductal gray (PAG) of male rats after acute cold stress and effects of endogenous antiopiate peptides Tyr-W-MIF-1 and Tyr-KMIF-1 on nociception was studied. The nociception was measured by the paw pressure test. As control were used intact rats. Stress activates PAG as an important component of the descending inhibitory pain pathway and stress-induced analgesia. CB1 immunoreactivity appeared as puncta and was found in cell bodies, axons and dendrites. The morphometric analysis revealed that acute cold stress increases the density of CB1-immunoreactive neurons in PAG compared with expression in intact animals. Secund, the results showed that Tyr-K-MIF-1 and Tyr-W-MIF-1 decreased the density of CB1-immunoreactive neurons in PAG of control rats, acute cold stress and after acute cold stress and effects of endogenous antiopiate peptides Tyr-WMIF-1 and Tyr-K-MIF-on nociception