Enhanced Function of Prefrontal Serotonin 5-HT(2) Receptors in a Rat Model of Psychiatric Vulnerability

J Neurosci. 2010 Sep 8;30(36):12138-50. doi: 10.1523/JNEUROSCI.3245-10.2010.

Abstract

Prefrontal serotonin 5-HT(2) receptors have been linked to the pathogenesis and treatment of affective disorders, yet their function in psychiatric vulnerability is not known. Here, we examine the effects of 5-HT(2) receptors in a rat model of psychiatric vulnerability using electrophysiology, gene expression, and behavior. Following the early stress of chronic maternal separation, we found that serotonin has atypical 5-HT(2) receptor-mediated excitatory effects in the adult prefrontal cortex that were blocked by the 5-HT(2A) receptor antagonist MDL 100907. In the absence of a serotonergic agonist, the intrinsic excitability of the prefrontal cortex was not enhanced relative to controls. Yet, in response to stimulation of 5-HT(2) receptors, adult animals with a history of early stress exhibit heightened prefrontal network activity in vitro, enhanced immediate early gene expression in vivo, and potentiated head shake behavior. These changes arise in the absence of any major alteration of prefrontal 5-HT(2A/C) mRNA expression or 5-HT(2) receptor binding. Our microarray results and quantitative PCR validation provide insight into the molecular changes that accompany such enhanced 5-HT(2) receptor function in adult animals following early stress. We observed persistent prefrontal transcriptome changes, with significant enrichment of genes involved in cellular developmental processes, regulation of signal transduction, and G-protein signaling. Specific genes regulated by early stress were validated in an independent cohort, and several altered genes were normalized by chronic blockade of 5-HT(2) receptors in adulthood. Together, our results demonstrate enhanced prefrontal 5-HT(2) receptor function and persistent alterations in prefrontal gene expression in a rat model of psychiatric vulnerability.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • AIDS-Related Complex / genetics
  • AIDS-Related Complex / metabolism
  • Amphetamines / toxicity
  • Analysis of Variance
  • Animals
  • Animals, Newborn
  • Behavior, Animal
  • Disease Models, Animal
  • Dose-Response Relationship, Drug
  • Drug Interactions
  • Excitatory Amino Acid Antagonists / pharmacology
  • Gene Expression Regulation / drug effects
  • Gene Expression Regulation / physiology*
  • In Vitro Techniques
  • Ketanserin / pharmacokinetics
  • Maternal Deprivation
  • Membrane Potentials / drug effects
  • Membrane Potentials / physiology
  • Mental Disorders / chemically induced
  • Mental Disorders / pathology*
  • Neurons / drug effects
  • Neurons / physiology*
  • Patch-Clamp Techniques / methods
  • Prefrontal Cortex / cytology
  • Prefrontal Cortex / metabolism*
  • Protein Binding / drug effects
  • RNA, Messenger / metabolism
  • Rats
  • Rats, Sprague-Dawley
  • Receptors, Serotonin, 5-HT2 / genetics
  • Receptors, Serotonin, 5-HT2 / metabolism*
  • Serotonin / pharmacology
  • Serotonin Agents / pharmacology
  • Serotonin Antagonists / pharmacology
  • Tritium / pharmacokinetics

Substances

  • Amphetamines
  • Excitatory Amino Acid Antagonists
  • RNA, Messenger
  • Receptors, Serotonin, 5-HT2
  • Serotonin Agents
  • Serotonin Antagonists
  • Tritium
  • Serotonin
  • Ketanserin
  • 4-iodo-2,5-dimethoxyphenylisopropylamine