A thermosensory pathway that controls body temperature.
Defending body temperature against environmental thermal challenges is one of the most fundamental homeostatic functions that are governed by the nervous system. Here we describe a somatosensory pathway that essentially constitutes the afferent arm of the thermoregulatory reflex that is triggered by cutaneous sensation of environmental temperature changes. Using in vivo electrophysiological and anatomical approaches in the rat, we found that lateral parabrachial neurons are pivotal in this pathway by glutamatergically transmitting cutaneous thermosensory signals received from spinal somatosensory neurons directly to the thermoregulatory command center, the preoptic area. This feedforward pathway mediates not only sympathetic and shivering thermogenic responses but also metabolic and cardiac responses to skin cooling challenges. Notably, this 'thermoregulatory afferent' pathway exists in parallel with the spinothalamocortical somatosensory pathway that mediates temperature perception. These findings make an important contribution to our understanding of both the somatosensory system and thermal homeostasis -- two mechanisms that are fundamental to the nervous system and to our survival.
Nakamura
Kazuhiro
K
Neurological Sciences Institute, Oregon Health & Science University, Beaverton, OR 97006, USA. nakamura@ohsu.edu
Morrison
Shaun F
SF
D000200:Action Potentials / Q000502:physiology; D000344:Afferent Pathways / Q000502:physiology*; D000704:Analysis of Variance; D000818:Animals; D001831:Body Temperature; D001833:Body Temperature Regulation; D001917:Brachial Plexus / Q000166:cytology; D001921:Brain; D001931:Brain Mapping; D002772:Cholera Toxin / Q000378:metabolism; D004569:Electroencephalography / Q000379:methods; D018690:Excitatory Amino Acid Agonists / Q000494:pharmacology; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D006302:Health Services Research; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects; D009475:Neurons, Afferent / Q000502:physiology*; D010751:Phosphopyruvate Hydratase / Q000378:metabolism; D011301:Preoptic Area / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects; D051381:Rats; D017207:Rats, Sprague-Dawley
D018690:Excitatory Amino Acid Agonists; D018691:Excitatory Amino Acid Antagonists; D002772:Cholera Toxin; D010751:Phosphopyruvate Hydratase