The histaminergic tuberomammillary nucleus is critical for motivated arousal.
Obtaining food, shelter or water, or finding a mating partner are examples of motivated behaviors, which are essential to preserve the species. The full expression of such behaviors requires a high but optimal arousal state. We tested the idea that tuberomammillary nucleus (TMN) histamine neurons are crucial to generate such motivated arousal, using a model of the appetitive phase of feeding behavior. Hungry rats enticed with food within a wire mesh box showed intense goal-directed motor activity aimed at opening the box, an increase in core temperature, a fast histamine release in the hypothalamus and an early increase in Fos immunoreactivity in TMN and cortical neurons. Enticing with stronger-tasting food induced stronger motor, temperature and Fos immunoreactivity brain responses than ordinary food pellets. TMN lesion greatly decreased all of those responses. We conclude that histamine neurons increase arousal and vegetative activity, allowing the normal unfolding of voluntary, goal-directed behavior such as obtaining food.
Departamento de Fisiología y Biofísica, ICBM, Facultad de Medicina, Universidad de Chile, Santiago, Chile.
José Luis
JL
Valdés
Cristián
C
Sánchez
María Eugenia
ME
Riveros
Patrizio
P
Blandina
Marco
M
Contreras
Paula
P
Farías
Fernando
F
Torrealba
D000818:Animals; D001143:Arousal / Q000502:physiology*; D001522:Behavior, Animal / Q000502:physiology*; D001831:Body Temperature; D005247:Feeding Behavior / Q000502:physiology; D006632:Histamine / Q000378:metabolism*; D007026:Hypothalamic Area, Lateral / Q000166:cytology / Q000378:metabolism* / Q000473:pathology; D008297:Male; D009043:Motor Activity / Q000502:physiology; D009474:Neurons / Q000166:cytology / Q000378:metabolism; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D013315:Stress, Psychological
D016760:Proto-Oncogene Proteins c-fos; D006632:Histamine