Taste reactivity alterations after IL-1beta microinjection into the ventromedial hypothalamic nucleus of the rat.
The ventromedial hypothalamic nucleus (VMH) is a central site of action of interleukin-1beta (IL-1beta) induced feeding disturbances. This study was designed to elucidate taste-related perceptual and motivational processes potentially contributing to the anorexia and adipsia seen after bilateral IL-1beta microinjection into the VMH. A saccharin conditioned taste aversion (CTA) paradigm was tested after the central IL-1beta administration. To further investigate whether gustatory deficits are involved in development of the feeding alterations, IL-1beta induced changes of taste responsiveness were also studied in taste reactivity tests. Administration of the cytokine into the VMH did not cause the development of CTA. During taste reactivity tests, however, IL-1beta treated rats displayed significantly poorer ingestive reactions to pleasant taste stimuli than did animals of the control group. In addition, the aversive responses of IL-1beta injected rats to pleasant tastes were significantly more robust than those of control animals. The cytokine treated animals also showed stronger aversion than ingestion to hedonically positive tastes. The present findings indicate that (1) anorexigenic and adipsogenic consequences of IL-1beta microinjection into the VMH are not due to development of cytokine induced CTA; and (2) hedonic responsiveness to palatable tastes is processed by IL-1beta mediated neural mechanisms in the VMH.
Takács
Gábor
G
Institute of Physiology and Neurophysiology Research Group of the Hungarian Academy of Sciences, Pécs University, Medical School, H-7624 Pécs, Szigeti Street 12, Hungary. gabor.takacs@aok.pte.hu
Lukáts
Balázs
B
Papp
Szilárd
S
Szalay
Csaba
C
Karádi
Zoltán
Z
D000818:Animals; D000855:Anorexia / Q000503:physiopathology; D001362:Avoidance Learning / Q000187:drug effects; D003214:Conditioning, Classical / Q000187:drug effects; D004408:Dysgeusia / Q000503:physiopathology*; D005247:Feeding Behavior / Q000187:drug effects; D007276:Injections, Intraventricular; D053583:Interleukin-1beta / Q000008:administration & dosage*; D008297:Male; D008845:Microinjections; D051381:Rats; D017208:Rats, Wistar; D013649:Taste / Q000502:physiology*; D014697:Ventromedial Hypothalamic Nucleus / Q000187:drug effects* / Q000502:physiology
D053583:Interleukin-1beta