An elusive neurotransmitter pathway in the skin may have been isolated by University of Oregon researchers, a discovery that, if confirmed, would be a leap forward in understanding how temperature regulation occurs. In other words, they may have found a major player in the machinery that allows people to release body heat and stay cool.
Experiments involving 11 young men and women looked closely at the relationship of the peptide substance P and its related neurokinin-receptor 1 (NK-1), both independently and in conjunction with nitric oxide activity in the skin. Both substance P and nitric oxide are widely distributed in the body and have been associated with many regulatory roles.
Reporting in a paper appearing online ahead of regular publication by the Journal of Physiology, two UO researchers concluded that when NK-1 receptor activity was diminished, so went the dilation of blood flow necessary for bringing warm blood from the body's core to the skin where the heat is lost by sweating.
For some 70 years, researchers have known that the rise in skin blood flow and sweating are linked. They've theorized but failed to definitively prove that the neurotransmitter vasoactive intestinal polypeptide (VIP) -- when released with the sweat-causing compound acetylcholine from specialized nerves in the skin during exercise or exposure to hot temperatures -- is what mediates the increased blood flow to the skin.
"A lot of people have thought that VIP is the main neurotransmitter, and on many fronts it has been the most likely candidate," said Christopher T. Minson, professor of human physiology at the University of Oregon. "What we've found is that the NK-1 receptor pathway is a major player in this response, and this finding could represent a paradigm shift. Our data implicate the NK-1 receptor pathway, and the primary neurotransmitter for this receptor in humans is substance P, suggesting that this is the putative vasodilator loca
Contact: Jim Barlow
University of Oregon