The area postrema (AP) and the parabrachial nucleus (PBN) are important sites for salmon calcitonin (sCT) to decrease evoked phasic dopamine release in the nucleus accumbens (NAc).
The pancreatic hormone amylin and its agonist salmon calcitonin (sCT) act via the area postrema (AP) and the lateral parabrachial nucleus (PBN) to reduce food intake. Investigations of amylin and sCT signaling in the ventral tegmental area (VTA) and nucleus accumbens (NAc) suggest that the eating inhibitory effect of amylin is, in part, mediated through the mesolimbic 'reward' pathway. Indeed, administration of the sCT directly to the VTA decreased phasic dopamine release (DA) in the NAc. However, it is not known if peripheral amylin modulates the mesolimbic system directly or whether this occurs via the AP and PBN. To determine whether and how peripheral amylin or sCT affect mesolimbic reward circuitry we utilized fast scan cyclic voltammetry under anesthesia to measure phasic DA release in the NAc evoked by electrical stimulation of the VTA in intact, AP lesioned and bilaterally PBN lesioned rats. Amylin (50μg/kg i.p.) did not change phasic DA responses compared to saline control rats. However, sCT (50μg/kg i.p.) decreased evoked DA release to VTA-stimulation over 1h compared to saline treated control rats. Further investigations determined that AP and bilateral PBN lesions abolished the ability of sCT to suppress evoked phasic DA responses to VTA-stimulation. These findings implicate the AP and the PBN as important sites for peripheral sCT to decrease evoked DA release in the NAc and suggest that these nuclei may influence hedonic and motivational processes to modulate food intake.
Institute of Veterinary Physiology, University of Zurich, Zurich, Switzerland.
Lynda
L
Whiting
Department of Neuroscience, Psychology and Behaviour, University of Leicester, Leicester, England.
James E
JE
McCutcheon
Institute of Veterinary Physiology, University of Zurich, Zurich, Switzerland.
Christina N
CN
Boyle
Department of Psychology, University of Illinois at Chicago, Chicago, IL, United States.
Mitchell F
MF
Roitman
Institute of Veterinary Physiology, University of Zurich, Zurich, Switzerland; Centre of Integrative Human Physiology, University of Zurich, Zurich, Switzerland. Electronic address: tomlutz@vetphys.uzh.ch.
Thomas A
TA
Lutz
D000818:Animals; D031608:Area Postrema / Q000187:drug effects*; D050071:Bone Density Conservation Agents / Q000494:pharmacology*; D002116:Calcitonin / Q000494:pharmacology*; D004298:Dopamine / Q000378:metabolism*; D004572:Electrolysis / Q000009:adverse effects; D008297:Male; D009714:Nucleus Accumbens / Q000378:metabolism*; D065823:Parabrachial Nucleus / Q000187:drug effects* / Q000293:injuries; D051381:Rats; D017208:Rats, Wistar; D012474:Salmon / Q000378:metabolism
D050071:Bone Density Conservation Agents; D002116:Calcitonin; D004298:Dopamine
Amylin; Dopamine; Food intake; Mesolimbic; Obesity; Reward