Background : The dorsomedial periaqueductal gray (dmPAG) is a mesencephalic area and has numerous functions including cardiovascular regulation. Because nitric oxide (NO) is present in the dmPAG, here we investigate, the probable cardiovascular effect of NO in the dmPAG. Methods : Five groups ( n = 6 for each group) were used as follows: (1) control; (2) L- NAME ( N G - nitro- L- arginine methyl ester, a NO synthase inhibitor, 90 nmol); (3) L- arginine (L- Arg, a precursor for NO, 60 nmol); (4) Sodium nitroprusside (SNP, a NO donor, 27 nmol); and (5) L- Arg + L- NAME. The cardiovascular parameters were re-corded by a Power Lab device after cannulation of the femoral artery. Drugs were injected using a stereotaxic instrument. The changes (Δ) in systolic blood pressure (SBP), mean arterial pressure (MAP), and heart rate (HR) were calculated at different times and compared to the control group. Results : Microinjection of L- NAME significantly increased ΔSBP, ΔMAP, and ΔHR more than saline (from p < 0.05 to p < 0.001). L- Arg only significantly increased ΔHR ( p < 0.05). In the L- Arg + L- NAME group, the above parameters also significantly in-creased (from p < 0.01 to p < 0.05) but not as significantly as with L- NAME alone. Microinjection of SNP significantly decreased ΔSBP and ΔMAP more than in the control and L- NAME groups (from p < 0.01 to p < 0.001), but ΔHR did not change significantly. Conclusion : The results indicated that NO in dmPAG has an inhibitory effect on car-diovascular responses in anesthetized rats.

Mohammad Najaftomaraei;Atiyeh Ghorbani;Alireza Rahimi;Reza Mohebbati;Sogol Sherkat;Mohammad Naser Shafei

Department of Physiology, Faculty of Medicine , Mashhad University of Medical Sciences , Mashhad , Iran;Material Science and Metallurgy Engineering , Islamic Azad University -Karaj Branch , Karaj , Iran;Department of Physiology, Faculty of Medicine , Gonabad University of Medical Sciences , Gonabad , Iran;Applied Biomedical Research Center , Mashhad University of Medical Sciences , Mashhad , Iran;Department of Physiology, School of Medicine , Sabzevar University of Medical Sciences , Sabzevar , Iran;Division of Neurocognitive Sciences, Psychiatry and Behavioral Sciences Research Center , Mashhad University of Medical Sciences , Mashhad , Iran

动物模型与实验医学（英文）

[1]Mohammad Najaftomaraei;Atiyeh Ghorbani;Alireza Rahimi;Reza Mohebbati;Sogol Sherkat;Mohammad Naser Shafei-.The role of nitric oxide in the dorsomedial periaqueductal gray ( dmPAG ) column in cardiovascular responses in urethane- anesthetized male rats)[J].动物模型与实验医学（英文）,2022(06):557-564

dmPAG,corded,stereotaxic,Microinjection

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