Synaptic and paracrine mechanisms at carotid body arterial chemoreceptors

摘要: Mammalian carotid bodies are the main peripheral arterial chemoreceptors, strategically located at bifurcation of common artery. When stimulated these receptors initiate compensatory respiratory and cardiovascular reflexes to maintain homeostasis. Thus, in response low oxygen (hypoxia) or increased CO2/H+ (acid hypercapnia), chemoreceptor type I cells depolarize release excitatory neurotransmitters, such as ATP, which stimulate postsynaptic P2X2/3 on afferent nerve terminals. The discharge is shaped by autocrine paracrine mechanisms involving both inhibitory neuromodulators adenosine, serotonin (5-HT), GABA dopamine. Recent evidence suggests that activation P2Y2 adjacent glia-like II may help boost ATP signal via opening pannexin-1 channels. presence an efferent innervation, mediated nitric oxide, provides additional control discharge. broad array their appears endow body with a remarkable plasticity, most apparent during natural pathophysiological conditions associated chronic sustained intermittent hypoxia.