The Role of Central and Peripheral α- and ß-Adrenoceptors in the Control of Cardiovascular Function
Central α2-Adrenoceptor. α2-Adrenoceptors exist postsynaptically on dendrites of neurons in the nucleus tracus solitarii (NTS), which is the first synapse in the central component of the cardiovascular reflex loop. Inhibitory neurons from the NTS course to the vasomotor center (VMC), while excitatory neurons from the NTS traverse to the dorsal motor nucleus of the vagus (DMNV). Stimulation of α2-adrenoceptors in the NTS by central α2-adrenoceptor agonists, such as Clonidine, results in the activation of the inhibitory neurons to the VMC, causing sympathetic outflow to the peripheral vasculature, heart, and kidney to be reduced. Consequently, peripheral vascular resistance, heart rate, and renin release are decreased resulting in a reduction in blood pressure. In addition, stimulation of central α2-adrenoceptors results in the activation of the excitatory neurons to the DMNV, which causes enhanced cholinergic outflow to the heart, producing yet a further decrease in heart rate and cardiac output .
KeywordsRenal Blood Flow Inhibitory Neuron Excitatory Neuron Renin Release Adrenoceptor Agonist
Unable to display preview. Download preview PDF.
- 4.Langer SZ, Massingham R, Shepperson N (1980) Clin Sci (Oxford) 59:255sGoogle Scholar