To reheat, or to not reheat: that is the question: The efficacy of a local reheating protocol on mechanisms of cutaneous vasodilatation

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

“…Previously, we have noted that basal CVC was higher in the legs (~24 % max) compared to the forearms (~13 % max) (Del Pozzi and Hodges 2015b;Hodges and Del Pozzi 2014;Del Pozzi et al 2013), yet this difference was not observed in the present study (Fig. 1).…”

“…We previously reported that the initial vasodilatory response to local skin heating was lower in the leg than the forearm (Del Pozzi and Hodges 2015b;Hodges and Del Pozzi 2014;Del Pozzi et al 2013). Prior work examining the forearm demonstrated the initial peak response to local skin heating to be primarily driven by sensory nerve function (Minson et al 2001;Tew et al 2011a;Carter and Hodges 2011;Minson et al 2002).…”

“…Additionally, these studies have reported that sensory nerves do not appear to be involved in the secondary sustained vasodilatation during prolonged local skin heating. In our previous studies examining local heating-induced cutaneous vasodilatation, we found that the initial peak response of the leg was approximately 25-30 % lower than that observed in the skin of the forearm (Del Pozzi et al 2013;Del Pozzi and Hodges 2015b;Hodges and Del Pozzi 2014). We also recently reported that this regional difference was not due to sympathetic nerve involvement (Del Pozzi and Hodges 2015a).…”

“…To that end, we examined the effects of sensory nerve blockade, through the application of a topical eutectic mixture of local anaesthetic (EMLA) cream, on the vasodilatory response to local skin heating in the forearm and leg. Based on extant data of vasodilatation of the forearm and leg (Pawelczyk and Levine 2002;Minson et al 2001Minson et al , 2002Tew et al 2011a, b;Yamazaki and Yuge 2011;Yamazaki 2012;Metzler-Wilson and Wilson 2013) and our previous findings (Del Pozzi and Hodges 2015b;Hodges and Del Pozzi 2014;Del Pozzi et al 2013), we hypothesized that the blockade of sensory nerve function would reduce the initial vasodilatory response of the forearm more than that of the leg, such that there would be no difference in the initial vasodilatory response between the regions. This would indicate that these nerves play a key role in the initiation of vasodilatation to local skin heating, while sensory nerve function differs between the skin of the forearm and leg; thus providing a mechanistic basis for the higher initial peak previously observed in the skin of the forearm compared to leg.…”

“…1). Following baseline, the same heating protocol as used in our previous examinations of forearm and leg skin blood flow (Del Pozzi and Hodges 2015b;Hodges and Del Pozzi 2014;Del Pozzi et al 2013) was performed by increasing T loc by 3 °C min −1 until T loc had reached 42 °C (3 min in total). T loc was maintained at 42 °C typically for 35 min or until a stable plateau had been reached and verified by a trained investigator.…”