Local warming induced vasodilatation in the rabbit ear
The human digit and forearm skin have different responsive patterns following thermal stress. The underlying mechanisms are not well studied. The present study examined the role of the peripheral sensory nerve and adrenergic fibers in the local warming-induced vasodilatation in the conscious rabbit ear. Methods: Ear cutaneous perfusion was examined using a laser Doppler fluxmeter (LDF) probe attached to a temperature controlled thermal plate (Perimed). Two groups of rabbits were studied. Group I (n=5) had a great auricular nerve transection and group II (n=5) had a superior cervical ganglionectomy (total denervation). The contralateral ear was served as a control. After a baseline perfusion value was obtained (4 minutes at 24°C), the thermal plate temperature was increased to and maintained at 42°C for 4 minutes. The plate temperature then was reduced to 24°C for another 4 minutes. Results: Local warming (42°C) increased the ear cutaneous flow significantly (200% of baseline, p < 0.05). Superior cervical ganglionectomy significantly reduced blood flow changes following local warming (p < 0.05). However, great auricular nerve transection had no significant effect on the warming- induced vasodilation. Conclusions: Local warming increases cutaneous perfusion. The warming-induced vasodilatation is an adrenergic mechanism and the peripheral sensory input is not important in this process.