Role of 5-HT5A receptors in the consolidation of memory

Behav Brain Res. 2013 Sep 1:252:246-51. doi: 10.1016/j.bbr.2013.05.051. Epub 2013 Jun 2.

Abstract

5-HT5 receptor occurs in brain areas implicated in learning and memory. Hence, the effects (0.01-3.0 mg/kg) of SB-6995516 (a 5-HT5A receptor antagonist) in the associative learning task of autoshaping were studied. The results showed that post-training injection of SB-699551 decreased conditioned responses (CR) during short-term (STM; 1.5h; at 0.1mg/kg) and long-term memory (LTM; 24 h; at 3.0 mg/kg) relative to the vehicle animals. Moreover, considering that there are no selective 5-HT5A receptor agonists, next, diverse doses of the serotonin precursor l-tryptophan were studied during STM and LTM, showing that l-tryptophan (5-100mg/kg) facilitated performance, particularly at 50mg/kg. In interactions experiments, l-tryptophan (50 mg/kg) attenuated the impairment effect induced by SB-699551 (either 0.3 or 3.0 mg/kg). All together this evidence suggests that the blockade of 5-HT5A receptor appear to be able to impair STM and LTM (24 h), while its stimulation might facilitate it. Of course further investigation is necessary, meanly with selective 5-HT5A compounds are necessary.

Keywords: 5-HT Receptors; Autoshaping; Learning rat.

MeSH terms

  • Animals
  • Biphenyl Compounds / pharmacology
  • Brain / drug effects
  • Brain / metabolism*
  • Conditioning, Classical / drug effects
  • Conditioning, Classical / physiology
  • Dose-Response Relationship, Drug
  • Male
  • Memory / classification
  • Memory / drug effects
  • Memory / physiology*
  • Rats
  • Rats, Wistar
  • Receptors, Serotonin / metabolism*
  • Reinforcement, Psychology
  • Serotonin Antagonists / pharmacology
  • Time Factors
  • Tryptophan / pharmacology

Substances

  • Biphenyl Compounds
  • Receptors, Serotonin
  • SB-699551-A
  • Serotonin Antagonists
  • serotonin 5 receptor
  • Tryptophan