Infralimbic cortex activation and motivated arousal induce histamine release.
Appetitive behaviours occur in a state of behavioural and physiological activation that allows the optimal performance of these goal-directed behaviours. Here, we tested the hypothesis that histamine neurons under the command of the infralimbic cortex are important to provide behavioural activation. Extracellular histamine and serotonin were measured by microdialysis of the medial prefrontal cortex in behaving rats in parallel with a picrotoxin microinjection into the infralimbic cortex. The injection aroused the rats behaviourally, increased histamine release and decreased serotonin levels. Inhibition of the infralimbic cortex with muscimol produced the opposite effects on neurotransmitter release. The behavioural activation induced by motivating hungry rats with caged food was paralleled by an immediate histamine release, whereas awakening induced by tapping their microdialysis bowl increased serotonin, but not histamine levels. In conclusion, picrotoxin injection into the infralimbic cortex produces behavioural activation together with histamine release; in a similar manner, induction of an appetitive state produced histamine release, likely related to increased behavioural activation characteristic of an appetitive behaviour.
Pontificia Universidad Católica de Chile, Facultad de Ciencias Biológicas, Departamento de Fisiología, Alameda, Santiago, Chile.
María Eugenia
ME
Riveros
María Inés
MI
Forray
Fernando
F
Torrealba
D000818:Animals; D001143:Arousal / Q000187:drug effects / Q000502:physiology*; D002408:Catheters, Indwelling; D002540:Cerebral Cortex / Q000187:drug effects / Q000502:physiology*; D002851:Chromatography, High Pressure Liquid; D058785:GABA-A Receptor Agonists / Q000494:pharmacology; D058787:GABA-A Receptor Antagonists / Q000494:pharmacology*; D006632:Histamine / Q000378:metabolism; D006636:Histamine Release / Q000187:drug effects / Q000502:physiology*; D006815:Hunger / Q000502:physiology; D008297:Male; D017551:Microdialysis; D009042:Motivation / Q000187:drug effects / Q000502:physiology*; D009118:Muscimol / Q000494:pharmacology; D009474:Neurons / Q000187:drug effects / Q000502:physiology; D010852:Picrotoxin / Q000494:pharmacology*; D017207:Rats, Sprague-Dawley; D011963:Receptors, GABA-A / Q000378:metabolism; D012701:Serotonin / Q000378:metabolism
D058785:GABA-A Receptor Agonists; D058787:GABA-A Receptor Antagonists; D006632:Histamine; D009118:Muscimol; D010852:Picrotoxin; D011963:Receptors, GABA-A; D012701:Serotonin