Gastric saline infusion reduces ultrasonic vocalizations and brown fat activity in suckling rat pups.
Under standard conditions involving isolation and cooling, it has been documented that intraoral infusion of milk and injection of the intestinal peptide cholecystokinin (CCK) result in an attenuation in ultrasonic vocalizations (USV) emitted by infant rat pups. One of the most effective stimuli in inhibiting ingestion in suckling rat pups is gastric distension, but the effect of gastric distension on USV production has not been reported. In this experiment, we subjected infant rats to intragastric infusion of isotonic saline (2% body weight) to produce a natural level of gastric distension and hydration. We found that this stimulus resulted in a powerful reduction in USV emissions in isolated 10-day-old rats. In a subsequent experiment, we found that gastric saline infusion also diminished brown adipose tissue (BAT) thermogenesis. There were different time courses of the gastric saline infusion effects on BAT thermogenesis and on USV emissions, however, suggesting that these processes may be independently regulated. We hypothesize that this stimulus induces a transient activation of the parasympathetic nervous system, which overrides the sympathetic control of BAT and USV production.
Nelson
Eric E
EE
Department of Psychology, Indiana University Bloomington, IN 47405, USA.
Alberts
Jeffrey R
JR
D002001:Adipose Tissue, Brown / Q000502:physiology*; D000818:Animals; D000831:Animals, Newborn / Q000502:physiology*; D001143:Arousal / Q000502:physiology*; D001833:Body Temperature Regulation / Q000502:physiology; D002766:Cholecystokinin / Q000502:physiology; D005260:Female; D008297:Male; D009042:Motivation; D051381:Rats; D017207:Rats, Sprague-Dawley; D012528:Satiety Response / Q000502:physiology*; D013391:Sucking Behavior / Q000502:physiology*; D014465:Ultrasonics; D014828:Vocalization, Animal / Q000502:physiology*
D002766:Cholecystokinin