The Journal of Neuroscience, June 3, 2009, 29(22):7330-7340; doi:10.1523/JNEUROSCI.5924-08.2009
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Behavioral/Systems/Cognitive
A Discrete GABAergic Relay Mediates Medial Prefrontal Cortical Inhibition of the Neuroendocrine Stress Response
Jason J. Radley,1
Kristin L. Gosselink,2 and
Paul E. Sawchenko1
1Laboratory of Neuronal Structure and Function, The Salk Institute for Biological Studies and Clayton Medical Research Foundation, La Jolla, California 92037, and 2Department of Biological Sciences, University of Texas at El Paso, El Paso, Texas 79968
Correspondence should be addressed to Dr. Jason J. Radley, Laboratory of Neuronal Structure and Function, The Salk Institute, 10010 North Torrey Pines Road, La Jolla, CA 92037. Email: radley{at}salk.edu
Complementing its roles in cognitive and affective information processing, the medial prefrontal cortex (mPFC) is a nodal point of a limbic forebrain circuit that modulates stress-related homeostatic mechanisms, including the hypothalamic–pituitary–adrenal (HPA) axis. mPFC influences on HPA output are predominantly inhibitory and emanate from the prelimbic and/or dorsal anterior cingulate cortical fields (PL and ACd, respectively). mPFC projections do not target HPA effector neurons in the paraventricular hypothalamic nucleus (PVH) directly, distributing instead to nearby forebrain regions, including some that house GABAergic neurons implicated in inhibitory PVH control. To identify pathway(s) subserving HPA-inhibitory mPFC influences, an initial screen for sources of GABAergic input to PVH whose sensitivity to an acute emotional (restraint) stress was diminished by PL/ACd lesions identified a discrete region of the anterior bed nucleus of the stria terminalis (aBST) as a candidate for fulfilling this role. Anatomical tracing experiments confirmed projections from PL (but not ACd) to implicated aBST cell groups, and from these to PVH. Finally, selective immunotoxin-mediated ablation of GABAergic aBST neurons recapitulated the effects of PL/ACd lesions on acute stress-induced activation of HPA output. The identification of a proximate mediator of HPA-inhibitory limbic influences provides a framework for clarifying how inhibitory neural and hormonal controls of HPA output are integrated, adaptations of the axis to chronic stress are effected, and how endocrine abnormalities may contribute to stress-related psychiatric illnesses in which mPFC dysfunction is implicated.
Received Dec. 12, 2008;
revised April 9, 2009;
accepted April 30, 2009.
Correspondence should be addressed to Dr. Jason J. Radley, Laboratory of Neuronal Structure and Function, The Salk Institute, 10010 North Torrey Pines Road, La Jolla, CA 92037. Email: radley{at}salk.edu