Independence of ultrasonic vocalization and thermogenic responses in infant rats.
Ultrasonic vocalizations (USV) normally accompany brown adipose tissue (BAT) thermogenesis in infant rats exposed to cold. BAT activation (measured by implanted thermistors) was pharmacologically blocked with hexamethonium (20 mg/kg ip) in 12-13-day-old pups, but they nevertheless showed normal USV responses to cold. Activation of BAT in warm pups by norepinephrine (800 micrograms/kg sc) failed to elicit USV. It is concluded that BAT activation is neither necessary nor sufficient for USV production. To evaluate how tightly the two responses may be coupled centrally, rat pups deprived of nutrients for 24 hr, in which sympathetic activation is known to be inhibited centrally (Bignall, Heggeness, & Palmer, 1975), were studied. These pups vocalized with the same latency in response to cold as normals but failed to show evidence of concurrent BAT activation. It is concluded that USV and BAT thermogenesis are normally elicited together by cold but are not tightly linked physiologically.
Hofer
M A
MA
Department of Developmental Psychobiology, New York State Psychiatric Institute, New York 10032.
Shair
H N
HN
D002001:Adipose Tissue, Brown / Q000502:physiology*; D000818:Animals; D000831:Animals, Newborn; D001143:Arousal / Q000502:physiology*; D001833:Body Temperature Regulation / Q000502:physiology*; D005260:Female; D007823:Laryngeal Nerves / Q000502:physiology; D008297:Male; D008426:Maternal Deprivation; D009638:Norepinephrine / Q000502:physiology; D010101:Oxygen Consumption / Q000502:physiology; D011149:Pons / Q000502:physiology; D051381:Rats; D011919:Rats, Inbred Strains; D014465:Ultrasonics; D014828:Vocalization, Animal / Q000502:physiology*
D009638:Norepinephrine