An in vivo dialysis and behavioural study of the release of 5-HT by p-chloroamphetamine in reserpine-treated rats

Br J Pharmacol. 1989 May;97(1):206-12. doi: 10.1111/j.1476-5381.1989.tb11943.x.


1. Reserpine (2.5 mg kg-1 i.p.) decreased rat brain 5-hydroxytryptamine (5-HT) by 86% 24 h later but most components of the 5-HT-dependent behavioural syndrome induced by p-chloroamphetamine (PCA, 5 mg kg-1 i.p.) or 5-methoxy-N,N-dimethyltryptamine (5-MeODMT, 5 mg kg-1 i.p.) over 1 h after administration were unaffected. However, Straub tail was increased after giving PCA or 5-MeODMT and head weaving was decreased after giving 5-MeODMT. 2. Frontal cortex extracellular 5-HT concentrations of vehicle pretreated rats before injection of PCA, as calculated from dialysate 5-HT concentrations, were about 1/1000th of corresponding brain values. Extracellular 5-hydroxyindoleacetic acid (5-HIAA) and brain values were comparable with each other. Dialysate 5-HT increased after PCA with peak values at 20-40 min. 3. Reserpine pretreatment reduced dialysate 5-HT concentration before PCA was given but the net increase (AUC) over the 1 h after PCA did not differ significantly from that seen in animals pretreated with vehicle. Dialysate 5-HIAA values slowly decreased after PCA injection in both reserpine and vehicle pretreated groups. 4. The results suggest that PCA causes the 5-HT syndrome by releasing 5-HT from the neuronal cytoplasm but that physiological release of 5-HT occurs from vesicular stores.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amphetamines / pharmacology*
  • Animals
  • Behavior, Animal / drug effects*
  • Brain Chemistry / drug effects*
  • Catecholamines / metabolism
  • Dialysis
  • Male
  • Methoxydimethyltryptamines / pharmacology
  • Motor Activity / drug effects
  • Rats
  • Rats, Inbred Strains
  • Reserpine / pharmacology*
  • Serotonin / metabolism*
  • Stereotyped Behavior / drug effects
  • p-Chloroamphetamine / pharmacology*


  • Amphetamines
  • Catecholamines
  • Methoxydimethyltryptamines
  • Serotonin
  • p-Chloroamphetamine
  • Reserpine