p-Chloroamphetamine treatment modifies evoked responses to sinusoidal gratings in the pigeon optic tectum

Vis Neurosci. 1989;2(2):147-52. doi: 10.1017/s0952523800012001.

Abstract

This study was performed in order to establish whether selective depletion of serotonin (5-HT) and its metabolite 5-hydroxyindoleacetic acid (5-HIAA) in the pigeon optic tectum (TeO) induced by p-chloroamphetamine (p-CA) modified tectal evoked potentials (TEPs). TEPs in response to sinusoidal gratings of different contrast, spatial and temporal frequency were recorded in control pigeons and in pigeons intraperitoneally injected with p-CA (10 mg/kg; two administrations in consecutive days). TEPs of p-CA treated pigeons, as compared to those of control pigeons, were reduced in amplitude as a function of contrast, spatial and temporal frequency. In addition, TEPs of p-CA treated pigeons differed from those recorded in controls in their transfer characteristics of contrast and spatial frequency. In particular, TEPs of p-CA treated pigeons did not saturate at moderate contrast, unlike those of controls. Furthermore, the TEP spatial tuning in p-CA treated pigeons is broader than that in controls; it thus suggests a reduction of spatial-frequency selectivity. These findings indicate that a selective neurotoxin for serotonergic systems, such as p-CA, can serve as a useful denervation tool for the study of the serotonergic function in the pigeon TeO. In addition, selective changes of TEP properties suggest the possibility that serotonergic afferents play a modulatory role on the receptive-field characteristics of tectal neurons.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Analysis of Variance
  • Animals
  • Columbidae / physiology*
  • Evoked Potentials / drug effects
  • Female
  • Hydroxyindoleacetic Acid / metabolism
  • Male
  • Photic Stimulation / methods
  • Serotonin / metabolism
  • Superior Colliculi / metabolism
  • Superior Colliculi / physiology*
  • p-Chloroamphetamine / pharmacology*

Substances

  • Serotonin
  • Hydroxyindoleacetic Acid
  • p-Chloroamphetamine