title: Differential activation of the prefrontal cortex and amygdala following psychological stress and colorectal distension in the maternally separated rat.
abstract: Visceral hypersensitivity is a hallmark of many clinical conditions and remains an ongoing medical challenge. Although the central neural mechanisms that regulate visceral hypersensitivity are incompletely understood, it has been suggested that stress and anxiety often act as initiating or exacerbating factors. Dysfunctional corticolimbic structures have been implicated in disorders of visceral hypersensitivity such as irritable bowel syndrome (IBS). Moreover, the pattern of altered physiological responses to psychological and visceral stressors reported in IBS patients is also observed in the maternally separated (MS) rat model of IBS. However, the relative contribution of various divisions within the cortex to the altered stress responsivity of MS rats remains unknown. The aim of this study was to analyze the cellular activation pattern of the prefrontal cortex and amygdala in response to an acute psychological stressor (open field) and colorectal distension (CRD) using c-fos immunohistochemistry. Several corticoamygdalar structures were analyzed for the presence of c-fos-positive immunoreactivity including the prelimbic cortex, infralimbic cortex, the anterior cingulate cortex (both rostral and caudal) and the amygdala. Our data demonstrate distinct activation patterns within these corticoamygdalar regions including differential activation in basolateral versus central amygdala following exposure to CRD but not the open field stress. The identification of this neuronal activation pattern may provide further insight into the neurochemical pathways through which therapeutic strategies for IBS could be derived.
authors: Department of Anatomy and Neuroscience, University College Cork, Ireland; Laboratory of Neurogastroenterology, Alimentary Pharmabiotic Centre, University College Cork, Ireland.
authors: V D
authors: VD
authors: Felice
authors: Laboratory of Neurogastroenterology, Alimentary Pharmabiotic Centre, University College Cork, Ireland.
authors: S M
authors: SM
authors: Gibney
authors: Laboratory of Neurogastroenterology, Alimentary Pharmabiotic Centre, University College Cork, Ireland.
authors: R D
authors: RD
authors: Gosselin
authors: Department of Anatomy and Neuroscience, University College Cork, Ireland; Department of Psychiatry, University College Cork, Ireland.
authors: T G
authors: TG
authors: Dinan
authors: Department of Anatomy and Neuroscience, University College Cork, Ireland; Laboratory of Neurogastroenterology, Alimentary Pharmabiotic Centre, University College Cork, Ireland. Electronic address: somahony@ucc.ie.
authors: S M
authors: SM
authors: O'Mahony
authors: Department of Anatomy and Neuroscience, University College Cork, Ireland; Laboratory of Neurogastroenterology, Alimentary Pharmabiotic Centre, University College Cork, Ireland.
authors: J F
authors: JF
authors: Cryan
mesh_terms: D000679:Amygdala / Q000503:physiopathology*; D000704:Analysis of Variance; D000818:Animals; D000831:Animals, Newborn; D003106:Colon / Q000503:physiopathology*; D004195:Disease Models, Animal; D005106:Exploratory Behavior / Q000502:physiology; D005260:Female; D008297:Male; D008426:Maternal Deprivation; D017397:Prefrontal Cortex / Q000503:physiopathology*; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D018709:Statistics, Nonparametric; D013315:Stress, Psychological / Q000473:pathology*; D059265:Visceral Pain / Q000473:pathology*
chemical_list: D016760:Proto-Oncogene Proteins c-fos
keywords: c-fos; colorectal distension; corticoamygdalar system; maternal separation; neuronal activation; stress