P2 receptors in the central and peripheral nervous systems modulating sympathetic vasomotor tone.
Arterial pressure depends on the level of activity of sympathetic vasoconstrictor outflow to blood vessels. This activity is generated in the central nervous system, and involves inputs from a variety of brain regions projecting to sympathetic preganglionic neurones. Of especial interest are a group of neurones in the rostral ventrolateral medulla (RVLM), as they have been demonstrated to have a fundamental role in reflex regulation of the cardiovascular system, and in generation of tonic drive to sympathetic outflow. Sympathetic outflow to blood vessels is additionally modulated at sympathetic ganglia, and at the peripheral terminals of sympathetic nerves. This review considers the role of P2 purine receptors in this neural pathway. Ionotropic P2X receptors are expressed in the RVLM, in sympathetic ganglia, and at the sympathetic neuromuscular junction, and mediate fast excitatory neurotransmission, indicating a general role for ATP as a regulator of sympathetic vasomotor tone. P2Y receptors couple to G proteins and mediate slower signalling to ATP; they have been reported to inhibit prejunctionally neurotransmission at the peripheral terminals of sympathetic nerves, but little is known about their possible role in the central nervous system and in sympathetic ganglia.
Ralevic
V
V
School of Biomedical Sciences, University of Nottingham Medical School, Queen's Medical Centre, NG7 2UH, Nottingham, UK. vera.ralevic@nottingham.ac.uk
D000255:Adenosine Triphosphate / Q000502:physiology; D000818:Animals; D002490:Central Nervous System / Q000502:physiology*; D006801:Humans; D009129:Muscle Tonus / Q000502:physiology*; D009131:Muscle, Smooth, Vascular / Q000294:innervation* / Q000502:physiology*; D017933:Peripheral Nervous System / Q000502:physiology*; D018048:Receptors, Purinergic P2 / Q000502:physiology*; D013564:Sympathetic Nervous System / Q000502:physiology*
D018048:Receptors, Purinergic P2; D000255:Adenosine Triphosphate