Spinal Reflex Control of Arterial Blood Pressure: The Role of TRP Channels and Their Endogenous Eicosanoid Modulators

Abstract

The spinal cord is an important integrative center for blood pressure control. Spinal sensory fibers send projections to sympathetic preganglionic neurons of the thoracic spinal cord and drive sympathetically-mediated increases in blood pressure. While these reflexes responses occur in able-bodied individuals, they are exaggerated following interruption of descending control – such as occurs following spinal cord injury. Similar reflex control of blood pressure may exist in disease states, other than spinal cord injury, where there is altered input to sympathetic preganglionic neurons. This review primarily focuses on mechanisms wherein visceral afferent information traveling via spinal nerves influences sympathetic nerve activity and blood pressure. There is an abundance of evidence for the widespread presence of this spinal reflex arch originating from virtually every visceral organ and thus having a substantial role in blood pressure control. Additionally, this review highlights specific endogenous eicosanoid species, which modulate the activity of afferent fibers involved in this reflex, through their interactions with transient receptor potential (TRP) cation channels.

Chronic Pain-Associated Cardiovascular Disease: The Role of Sympathetic Nerve Activity

“…Although tonically low, sympathetic activity can be markedly increased following the activation of spinal sympathetic pathways. The spinal sympathetic reflex circuitry is similar in composition to the spinal motor reflex circuits that drive muscle contraction in response to muscle stretch or cutaneous stimulation, and like spinal motor reflexes, the spinal sympathetic reflexes are exaggerated by spinal cord transection [ 87 , 88 , 89 , 90 , 91 ]. The spinal motoneurons are controlled by the descending corticothalamic projections, which exhibit a tonic inhibitory drive to the motoneurons [ 92 , 93 ].…”

Excessive dietary linoleic acid promotes plasma accumulation of pronociceptive fatty acyl lipid mediators

“…It is unclear whether widespread dietary campaigns aimed to reducing cardiovascular disease risk by reducing dietary intake of saturated fat may have inadvertently promoted nociceptive hypersensitivity and/or pain in the population, by increasing LA consumption. Furthermore, given that pain is associated with the development of cardiovascular disease 21 and nociceptive hypersensitivity may contribute to increasing systemic blood pressure 22 , it remains to be determined whether cardiovascular disease risk could be further reduced if saturated fats were replaced with monounsaturated fatty acids, like OA, which are not substrates for the LM-producing enzymes.…”

Controls of Central and Peripheral Blood Pressure and Hemorrhagic/Hypovolemic Shock

“…The spinal cord is an important integrative center of sympathetic responses essential for blood pressure control [67]. The effect of the sympathetic nervous system is highly crucial in regulating blood pressure because postganglionic sympathetic nerves innervate blood vessels and affect peripheral resistance by modulating vascular smooth-muscle tone.…”