activates only 1 receptor at low dose, but other receptors at higher doses
Alphas and Betas
Dopaminergic (inhibitory)-vessels dilate and blood flow increases=improved circulation [only dopamine can activate this receptor]
Muscarinic receptors(parasympathetic)-located on target tissue affected by postganglionic neurons in parasympathetic nervous system. ACTION: stimulate smooth muscle and gland secretion; in heart-decreased heart rate and force of contraction.
Nicotinic(sympathetic and parasympathetic)-located at ganglionic synapse in both symp. and parasymp. ACTION-stimulate smooth muscle and gland secretion
released by Cholinergic nerves-nerves that release Acetycholine (Ach)