Tahereh Nikyar - Department of Physiology, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
Mahmoud Hosseini - Division of Neurocognitive Sciences, Psychiatry and Behavioral Sciences Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
Saeed Niazmand - Department of Physiology, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
Mohammad Naser Shafei - Neurogenic Inflammation Research Center, Mashhad University of Medical Sciences, Mashhad, Iran

Objective(s): Cholinergic neurons are important neurons in the Pedunculopontine tegmental nucleus (PPT). In this study, nicotinic receptor of the PPT in central cardiovascular regulation in the anesthetized rat was evaluated. Materials and Methods: Saline, acetylcholine (Ach; doses: ۹۰ and ۱۵۰ nmol), hexamethonium (Hexa; doses: ۱۰۰ and ۳۰۰ nmol) and higher doses of Hexa (۳۰۰ nmol) + Ach (۱۵۰ nmol) microinjected into the PPT. The femoral artery was cannulated and cardiovascular responses were continuously recorded by a power lab system. After injection of drugs, peak changes of mean arterial pressure (∆MAP), systolic blood pressure (∆SBP) and heart rate (∆HR) calculated and compared with saline group.Results: The ∆SBP and ∆MAP significantly decreased by two doses of Ach (PConclusion: These results indicate that nicotinic receptor of the PPT has an inhibitory effect on ∆HR with no significant effect on ∆MAP or ∆SBP.

Acetylcholine, Blood pressure Hexamethonium, Nicotinic receptor, Pedunculopontine tegmental nucleus