The contribution of sensory nerves to cutaneous vasodilatation of the forearm and leg to local skin heating

Abstract

The differences in the initial vasodilatory peak to local skin heating between the forearm and the leg are due to the contribution of sensory nerves.

The contribution of sensory nerves to the onset threshold for cutaneous vasodilatation during gradual local skin heating of the forearm and leg

“…We observed that blockade of sensory nerve function (with topical EMLA cream) delayed the onset of vasodilatation, but the difference in the magnitude of the sustained vasodilatory response between limbs persisted (Hodges et al, 2015); however, sensory nerve blockade with EMLA abolished this difference between limbs and greatly increased time to onset of vasodilatation (both~150 s) (Hodges et al, 2015). Additionally, these temporal differences between regions and with sensory nerve blockade occurred for all phases of the local heating response.…”

“…Additionally, the participants were instructed not to eat for 1 h prior to the testing session, but were encouraged to drink water ad libitum. As in our laboratory's previous studies female participants were currently in the low hormone phase of their birth control routine as verified through self-report (Del Pozzi and Hodges, 2015a, 2015b, 2015cHodges et al, 2015).…”

“…In response to local skin heating, the magnitude of the initial peak is greater in the forearm compared to the leg. Sensory nerve blockade abolishes the difference in the initial peak response between the forearm and leg (Hodges et al, 2015). During prolonged skin heating, the leg presents with higher vasodilatation compared to the arm, which appears to be due to increased endothelial function (Hodges and Del Pozzi, 2014), a difference that is abolished with NOS inhibition (Del Pozzi et al, 2013).…”

“…Localized heating of the skin elicits a biphasic vasodilatory response. There is an early, rapid vasodilatation during the first 5 min of heating ('initial peak') that is dependent on local sensory nerve function (Carter and Hodges, 2011;Hodges et al, 2015;Minson et al, 2001;Strom et al, 2010;Tew et al, 2011). This is succeeded by a secondary, gradual and prolonged vasodilatation (plateau phase) that is dependent on endothelial nitric oxide (eNOS) (Hodges and Sparks, 2013;Kellogg et al, 2008Kellogg et al, , 2009 and endothelial derived hyperpolarizing factor (Brunt and Minson, 2012).…”

“…There are also clear temporal differences in the onset of vasodilatation in the skin of the forearm (~20 s) and leg (~50 s) (Del Pozzi and Hodges, 2015a;Hodges et al, 2015) in response to a standard local skin heating protocol (+ 3°C·min −1 ). We observed that blockade of sensory nerve function (with topical EMLA cream) delayed the onset of vasodilatation, but the difference in the magnitude of the sustained vasodilatory response between limbs persisted (Hodges et al, 2015); however, sensory nerve blockade with EMLA abolished this difference between limbs and greatly increased time to onset of vasodilatation (both~150 s) (Hodges et al, 2015).…”