Cocaine withdrawal enhances long-term potentiation induced by corticotropin-releasing factor at central amygdala glutamatergic synapses via CRF, NMDA receptors and PKA.
Cocaine addiction is an enduring, relapsing, behavioural disorder in which stressors reinstate cocaine-seeking even after prolonged abstinence. Evidence suggests that the 'anxiety-like' behaviour and stress associated with protracted withdrawal may be mediated by increased corticotropin-releasing factor (CRF) in the central nucleus of the amygdala (CeA), a part of the limbic circuitry engaged in the coding and transmission of stimulus-reward associations. In the present study we describe a long-lasting potentiation of glutamatergic transmission induced at lateral amygdala (LA)-to-CeA synapses by rat/human CRF. After 2 weeks of withdrawal from repeated intermittent exposure to cocaine, CRF-induced long-term potentiation (LTP) was greatly enhanced compared to the respective saline control group while, after short-term withdrawal (24 h), there was no significant difference between the two treatment groups, indicating alterations in CRF systems during protracted withdrawal from chronic cocaine. After prolonged withdrawal, CRF-induced LTP was dependent on activation of CRF2, CaV2.3 (R-type) calcium channels and intracellular signalling through protein kinase C in both saline- and cocaine-treated groups. The enhanced CRF-induced LTP after 2 weeks of withdrawal was mediated through augmented CRF1 receptor function, associated with an increased signalling through protein kinase A, and required N-methyl-D-aspartate (NMDA) receptors. Accordingly, single-cell recordings revealed a significantly increased NMDA/AMPA ratio after prolonged withdrawal from the cocaine treatment. These results support a role for CRF1 receptor antagonists as plausible treatment options during withdrawal from chronic cocaine and suggest Ca(V)2.3 blockers as potential candidates for pharmaceutical modulation of CRF systems.
Pollandt
Sebastian
S
University of Texas Medical Branch, Department of Pharmacology and Toxicology, Galveston, TX 77555-1031, USA. swpollan@utmb.edu
Liu
Jie
J
Orozco-Cabal
Luis
L
Grigoriadis
Dimitri E
DE
Vale
Wylie W
WW
Gallagher
Joel P
JP
Shinnick-Gallagher
Patricia
P
D000679:Amygdala / Q000187:drug effects*; D000818:Animals; D003042:Cocaine / Q000008:administration & dosage*; D003346:Corticotropin-Releasing Hormone / Q000494:pharmacology; D017868:Cyclic AMP-Dependent Protein Kinases / Q000502:physiology*; D018765:Dopamine Uptake Inhibitors / Q000008:administration & dosage*; D004305:Dose-Response Relationship, Drug; D004334:Drug Administration Schedule; D004347:Drug Interactions; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D018690:Excitatory Amino Acid Agonists / Q000494:pharmacology; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D018698:Glutamic Acid / Q000378:metabolism; D066298:In Vitro Techniques; D017774:Long-Term Potentiation / Q000187:drug effects* / Q000502:physiology; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D018019:Receptors, Corticotropin-Releasing Hormone / Q000502:physiology*; D016194:Receptors, N-Methyl-D-Aspartate / Q000502:physiology*; D013569:Synapses / Q000187:drug effects* / Q000378:metabolism; D000099052:CRF Receptor, Type 1
D018765:Dopamine Uptake Inhibitors; D004791:Enzyme Inhibitors; D018690:Excitatory Amino Acid Agonists; D018691:Excitatory Amino Acid Antagonists; D018019:Receptors, Corticotropin-Releasing Hormone; D016194:Receptors, N-Methyl-D-Aspartate; D018698:Glutamic Acid; D000099052:CRF Receptor, Type 1; D003346:Corticotropin-Releasing Hormone; D017868:Cyclic AMP-Dependent Protein Kinases; D003042:Cocaine