Morphine produces circuit-specific neuroplasticity in the bed nucleus of the stria terminalis.
The bed nucleus of the stria terminalis (BST) is a brain structure located at the interface of the cortex and the cerebrospinal trunk. The BST is a cluster of nuclei organized in a complex intrinsic network that receives inputs from cortical and subcortical sources, and that sends a widespread top-down projection. There is growing evidence that the BST is a key component in the neurobiological basis of substance abuse. In the present study, the regulation of excitatory inputs onto identified neurons in the BST was examined in rats treated chronically with morphine. Neurons projecting to the ventral tegmental area (VTA) were identified by retrograde transport of fluorescent microspheres and recorded in the whole-cell voltage clamp configuration in brain slices. Selective excitatory inputs to these neurons were electrically evoked with electrodes placed in the medial and lateral aspects of the dorsal BST. The chronic morphine treatment selectively increased AMPA-dependent excitatory postsynaptic currents in a subset of inputs activated by dorso-lateral stimulation in the BST. Inputs activated by medial stimulation were not affected by morphine. Likewise, the inputs to neurons that did not project to the VTA were not changed by morphine. Altogether, these results extend the understanding of neuronal circuits intrinsically sensitive to drugs of abuse within the BST.
Dumont
E C
EC
Department of Anesthesiology and Center for Neuroscience Studies, Queen's University, 99 University Avenue, Kingston, Ontario, Canada K7L 3N6. eric.dumont@queensu.ca
Rycroft
B K
BK
Maiz
J
J
Williams
J T
JT
D000818:Animals; D001931:Brain Mapping; D004334:Drug Administration Schedule; D004558:Electric Stimulation; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects / Q000502:physiology; D005456:Fluorescent Dyes; D009020:Morphine / Q000494:pharmacology*; D009294:Narcotics / Q000494:pharmacology; D009434:Neural Pathways / Q000033:anatomy & histology / Q000187:drug effects / Q000502:physiology; D009473:Neuronal Plasticity / Q000187:drug effects* / Q000502:physiology; D009293:Opioid-Related Disorders / Q000378:metabolism / Q000503:physiopathology; D009924:Organ Culture Techniques; D018408:Patch-Clamp Techniques; D051381:Rats; D017207:Rats, Sprague-Dawley; D018091:Receptors, AMPA / Q000187:drug effects / Q000378:metabolism; D012686:Septal Nuclei / Q000033:anatomy & histology / Q000187:drug effects* / Q000502:physiology; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology
D005456:Fluorescent Dyes; D009294:Narcotics; D018091:Receptors, AMPA; D009020:Morphine