Ultrasonic vocalizations are elicited from rat pups in the home cage by pentylenetetrazol and U50,488, but not naltrexone
Ultrasonic vocalizations are elicited from rat pups in the home cage by pentylenetetrazol and U50,488, but not naltrexone
Carden, S.E.; Bortot, A.T.; Hofer, M.A.
Behavioral Neuroscience 107(5): 851-859
1993
ISSN/ISBN: 0735-7044
PMID: 8280394
DOI: 10.1037/0735-7044.107.5.851
Although isolated rat pups emit ultrasonic vocalizations (USVs), those kept warm and undisturbed in the home cage with their littermates seldom do. Drugs were administered to 10-day-old pups in the home cage to determine whether pharmacological agents can elicit USV in this familiar environment. Ten-day-old Wistar rats were injected with U50.488, a highly selective kappa opioid agonist; pentylenetetrazol (PTZ), an anxiogenic drug that binds at the GABA-benzodiazepine receptor complex; or naltrexone (NLX), an opiate receptor blocker, and then were returned to their littermates in the home cage. U50,488 increased USV and activity levels, lowered body temperature, and disrupted contact with litter-mates. PTZ raised activity levels but had a smaller effect on vocalization rates and did not alter temperature or contact with littermates. Behavioral measures and body temperature were unchanged by NLX.