Evidence for beta1-adrenergic receptor involvement in amygdalar corticotropin-releasing factor gene expression: implications for cocaine withdrawal.
We previously showed that betaxolol, a selective beta(1)-adrenergic receptor antagonist, administered during early phases of cocaine abstinence, ameliorated withdrawal-induced anxiety and blocked increases in amygdalar beta(1)-adrenergic receptor expression in rats. Here, we report the efficacy of betaxolol in reducing increases in gene expression of amygdalar corticotropin-releasing factor (CRF), a peptide known to be involved in mediating 'anxiety-like' behaviors during initial phases of cocaine abstinence. We also demonstrate attenuation of an amygdalar beta(1)-adrenergic receptor-mediated cell-signaling pathway following this treatment. Male rats were administered betaxolol at 24 and 44 h following chronic cocaine administration. Animals were euthanized at the 48-h time point and the amygdala was microdissected and processed for quantitative reverse transcriptase-polymerase chain reaction and/or western blot analysis. Results showed that betaxolol treatment during early cocaine withdrawal attenuated increases in amygdalar CRF gene expression and cyclic adenosine monophosphate-dependent protein kinase regulatory and catalytic subunit (nuclear fraction) protein expression. Our data also reveal that beta(1)-adrenergic receptors are on amygdalar neurons, which are immunoreactive for CRF. The present findings suggest that the efficacy of betaxolol treatment on cocaine withdrawal-induced anxiety may be related, in part, to its effect on amygdalar beta(1)-adrenergic receptor, modulation of its downstream cell-signaling elements and CRF gene expression.
Rudoy
Carla A
CA
Department of Neurosurgery, Farber Institute for Neurosciences, Thomas Jefferson University, Philadelphia, PA 19107, USA. carla.rudoy@jefferson.edu
Reyes
Arith-Ruth S
AR
Van Bockstaele
Elisabeth J
EJ
D058671:Adrenergic beta-1 Receptor Antagonists; D000319:Adrenergic beta-Antagonists / Q000494:pharmacology / Q000627:therapeutic use; D000679:Amygdala / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D000818:Animals; D015784:Betaxolol / Q000494:pharmacology* / Q000627:therapeutic use; D002467:Cell Nucleus / Q000378:metabolism; D000697:Central Nervous System Stimulants / Q000633:toxicity; D003042:Cocaine / Q000633:toxicity*; D003346:Corticotropin-Releasing Hormone / Q000378:metabolism*; D017362:Cyclic AMP Response Element-Binding Protein / Q000378:metabolism; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D003593:Cytoplasm / Q000378:metabolism; D015870:Gene Expression; D008297:Male; D009474:Neurons / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D010766:Phosphorylation / Q000187:drug effects; D012333:RNA, Messenger / Q000378:metabolism; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley; D018342:Receptors, Adrenergic, beta-1 / Q000378:metabolism*; D013375:Substance Withdrawal Syndrome / Q000188:drug therapy / Q000378:metabolism*
D058671:Adrenergic beta-1 Receptor Antagonists; D000319:Adrenergic beta-Antagonists; D000697:Central Nervous System Stimulants; D017362:Cyclic AMP Response Element-Binding Protein; D012333:RNA, Messenger; D018342:Receptors, Adrenergic, beta-1; D003346:Corticotropin-Releasing Hormone; D017868:Cyclic AMP-Dependent Protein Kinases; D003042:Cocaine; D015784:Betaxolol