Dopaminergic and opioidergic mediations of tricyclic antidepressants in the learned helplessness paradigm
by
Besson A, Privat AM, Eschalier A, Fialip J
NeuroPsychoPharmacologie,
Universite d'Auvergne,
Laboratoire de Pharmacologie,
Faculte de Pharmacie, Clermont Ferrand, France.
Pharmacol Biochem Behav 1999 Nov; 64(3):541-8

ABSTRACT

The roles of dopaminergic and opioid neurotransmissions in the activity of three tricyclic antidepressants endowed with different monoamine-reuptake properties [desipramine (DESI), imipramine (IMI), amineptine (AMN)] were examined using a behavioral model of depression in rats; the learned helplessness paradigm. In this model, exposure of rats to inescapable shocks (day 1) produced a subsequent escape deficit in a shuttle box test (days 3, 4, and 5). The escape deficit was reversed by AMN, DESI, and IMI administered twice daily for 5 days (16 and 32 mg/kg/day, p < 0.05, days 3, 4, and 5). In addition, AMN tended to enhance the motor activity of rats during the intertrial intervals, but on the first shuttle-box test only (day 3: p < 0.05, control vs AMN). Haloperidol, a preferential D2 dopamine receptor antagonist, acutely injected IP (37.5 microg/kg), suppressed the behavioral activity of DESI and IMI but not that of AMN. Naloxone, a preferential mu-opioid receptor antagonist, acutely injected IP (0.5 mg/kg), suppressed the behavioral activity of IMI but not that of DESI and AMN. It is concluded that an increased dopaminergic activity is a neurochemical effect common to the different tricyclic antidepressants (via a presynaptic mechanism for AMN and a postsynaptic mechanism for DESI and IMI), whereas an increased mu-opioid neurotransmission does not appear to be essential.

TCAs
SSRIs
Options
Imipramine
Amineptine
Dumb drugs
Desipramine
TCAs v SSRIs
Antidepressants
Retarded depression
Antidepressant toxicity
Selectivity or multiplicity?
Imipramine and dopamine d1
Tricyclic antidepressants for depression
SSRIs compared with tricyclic antidepressants
Desipramine (Norpramin, Pertofrane) and mu-opioid receptors

Refs
and further reading

HOME
HedWeb
Nootropics
cocaine.wiki
Future Opioids
BLTC Research
MDMA/Ecstasy
Superhapiness?
Utopian Surgery?
The Abolitionist Project
The Hedonistic Imperative
The Reproductive Revolution
Critique of Huxley's Brave New World

The Good Drug Guide
The Responsible Parent's Guide
To Healthy Mood Boosters For All The Family