Evaluation of nicotinic receptor of pedunculopontine tegmental nucleus in central cardiovascular regulation in anesthetized rat

Abstract

<em><strong>Objective(s):</strong></em> 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. <br /><em><strong>Materials and Methods:</strong></em> Saline, acetylcholine (Ach; doses: 90 and 150 nmol), hexamethonium (Hexa; doses: 100 and 300 nmol) and higher doses of Hexa (300 nmol) + Ach (150 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.<br /><em><strong>Results:</strong> </em>The ∆SBP and ∆MAP significantly decreased by two doses of Ach (P<em><strong>Conclusion:</strong></em> These results indicate that nicotinic receptor of the PPT has an inhibitory effect on ∆HR with no significant effect on ∆MAP or ∆SBP.