Electroconvulsive shock increases the behavioural responses of rats to brain 5-hydroxytryptamine accumulation and central nervous system stimulant drugs | JoVE Visualize

Electroconvulsive shock increases the behavioural responses of rats to brain 5-hydroxytryptamine accumulation and central nervous system stimulant drugs

J P Evans, D G Grahame-Smith, A R Green

British Journal of Pharmacology|February 1, 1976

View abstract on PubMed

Summary

Electroconvulsive shock (ECS) alters brain serotonin activity. Repeated ECS enhances serotonin functional activity and neuronal sensitivity, potentially explaining electroconvulsive therapy

Area of Science:

Neuroscience
Psychopharmacology
Behavioral Science

Background:

Electroconvulsive therapy (ECT) is an effective treatment for severe depression.
The precise mechanisms underlying ECT's therapeutic effects remain incompletely understood.
Serotonin (5-HT) pathways are implicated in mood regulation and ECT's action.

Purpose of the Study:

To investigate the effects of electroconvulsive shock (ECS) on serotonin (5-HT) neurotransmission and associated behaviors in rats.
To determine whether single or repeated ECS alters 5-HT synthesis, accumulation, and functional activity.
To explore the impact of ECS on neuronal sensitivity and behavioral responses to psychotropic agents.

Main Methods:

Rats received single or repeated daily ECS (10 days).
Neurotransmitter concentrations (5-HT, 5-HIAA, tryptophan, noradrenaline, dopamine) and synthesis rates were measured.
Behavioral responses to L-tryptophan, tranylcypromine, 5-methoxy-N,N-dimethyltryptamine, and L-DOPA were assessed.
Latent period for pentylenetetrazol-induced convulsions was measured.

Main Results:

A single ECS transiently increased brain 5-HIAA but did not alter 5-HT synthesis or functional activity.
Repeated ECS (10 days) enhanced hyperactivity following L-tryptophan/tranylcypromine administration and 5-HT agonist stimulation.
Repeated ECS also enhanced locomotor activity with L-DOPA and shortened the pentylenetetrazol-induced convulsion latency.
Brain monoamine concentrations remained largely unchanged after repeated ECS.

Conclusions:

Repeated ECS, but not single ECS, appears to increase central 5-HT functional activity.
Enhanced behavioral responses suggest altered post-synaptic sensitivity to 5-HT receptor stimulation after repeated ECS.
Findings suggest that repeated ECS may enhance neuronal sensitivity, contributing to ECT's therapeutic efficacy.