22-kHz ultrasonic vocalization in rats as an index of anxiety but not fear: behavioral and pharmacological modulation of affective state.
Ultrasonic vocalization (USV) was found useful for differentiating fear and anxiety in rats. These affective states were established through a Pavlovian conditioning procedure. Danger stimulus, preceding unavoidable tail shock, elicited acute fear. Intertrial situational cues evoked anxiety. A safety signal (SS) indicating the omission of shock inhibited fear. Sustained 22-kHz USV characterized anxiety and was present between trials. A signal of danger resulted in immediate inhibition of vocalization, while a SS reversed this effect. These results are discussed in the context of three theories: Pavlovian, Bollesian and Konorskian. The anxiolytic drugs diazepam and buspirone (1 and 5 mg/kg) suppressed vocalization in the intertrial and SS periods. The reaction to the signal of danger remained complete inhibition of USV. Anxiogenic pentyletetrazole (1 and 5 mg/kg) enhanced intertrial vocalization, but did not affect its reoccurrence during the SS. Anxiogenic FG7142 (5 mg/kg) did not affect intertrial vocalization, but blocked its reappearance on the SS. It is suggested that the behavioral target of both anxiogenic drugs is different-pentyletetrazole supposedly exerts its anxiogenic effect by increasing situational anxiety, whereas FG7142 suppresses inhibition of fear.
Jelen
Piotr
P
Faculty for Rehabilitation, Academy of Physical Education, Marymoncka 34, P.O. Box 55, 00-968 Warsaw, Poland.
Soltysik
Stefan
S
Zagrodzka
Jolanta
J
D000818:Animals; D001007:Anxiety / Q000175:diagnosis* / Q000188:drug therapy / Q000503:physiopathology; D001522:Behavior, Animal; D002065:Buspirone; D002243:Carbolines / Q000494:pharmacology; D003214:Conditioning, Classical / Q000187:drug effects; D003937:Diagnosis, Differential; D003975:Diazepam / Q000494:pharmacology; D004195:Disease Models, Animal; D005239:Fear / Q000187:drug effects / Q000523:psychology*; D018756:GABA Antagonists / Q000494:pharmacology; D018757:GABA Modulators / Q000494:pharmacology; D008297:Male; D019964:Mood Disorders / Q000503:physiopathology*; D010433:Pentylenetetrazole / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D012016:Reference Values; D017366:Serotonin Receptor Agonists; D014465:Ultrasonics; D014828:Vocalization, Animal / Q000187:drug effects / Q000502:physiology*
D002243:Carbolines; D018756:GABA Antagonists; D018757:GABA Modulators; D017366:Serotonin Receptor Agonists; C035874:FG 7142; D003975:Diazepam; D002065:Buspirone; D010433:Pentylenetetrazole