title: Ultrasounds during morphine withdrawal in rats.
abstract: Ultrasounds (US) in rats may communicate affective states, as they occur only in highly significant situations such as maternal care, sex and aggression. Withdrawal from morphine is a manipulation which dramatically alters autonomic, somatic and motor functions; the present experiment demonstrated the production of US in this context and the influence of previous social experience in their production. Sixty male Long-Evans rats with distinct social experiences (social inexperience, defeat or copulation) underwent 72 h of continuous morphine exposure (4 x 75 mg morphine or placebo pellets) and subsequent withdrawal. The rats were observed for 10 min in equally treated pairs and while solitary at 6, 24 and 96 h after pellet removal. US were emitted by all groups and consisted primarily of two distributions of pure tone whistles with little frequency modulation: 1-2 s 21-25 kHz ("low") signals and the more prevalent 0.02-0.1 s 44-52 kHz ("high") signals. Morphine withdrawn rats lost weight, displayed wet dog shakes, were hypoactive and emitted threefold more US vocalizations with a fourfold greater duration than placebo controls. Defeat-experienced morphine withdrawn rats were more hypoactive than either socially inexperienced or copulatory experienced rats while increasing vocalization rates and total duration. This increased duration of ultrasounds included a shift in the distribution of individual US durations from less than 0.3 s to greater than 1.0 s. US are readily emitted at high rates in morphine withdrawn laboratory rats, which may implicate an opioid involvement in their generation.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Department of Psychology, Tufts University, Medford, MA 02155.
authors.forename: J A
authors.initials: JA
authors.lastname: Vivian
authors.forename: K A
authors.initials: KA
authors.lastname: Miczek
mesh_terms: D000374:Aggression / Q000523:psychology; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D001835:Body Weight / Q000187:drug effects; D008297:Male; D009020:Morphine / Q000494:pharmacology*; D009043:Motor Activity / Q000187:drug effects; D051381:Rats; D012919:Social Behavior; D013375:Substance Withdrawal Syndrome / Q000523:psychology*; D014828:Vocalization, Animal / Q000187:drug effects*
chemical_list: D009020:Morphine