Release of [Met]enkephalin in the central nucleus of the amygdala is increased by application of potassium in the substantia nigra.
Release of [Met]enkephalin immunoreactivity (Met-IR) in the central nucleus of the amygdala (ACE) was investigated in vivo in anesthetized rats implanted with push-pull cannulae. A stable spontaneous release of this peptide (1.3 fmol/15 min fraction) could be measured in the superfusates using a highly sensitive radioimmunoassay. The addition to the superfusion medium of cocktail of peptidase inhibitors increased three times the spontaneous release of the peptide. Superfusion with 30 mM potassium increased ten times the release of the peptide. Chemical stimulation of the substantia nigra with K+ enhanced four times the Met-IR release in the ipsilateral ACE. The dopaminergic component of the nigro-amygdaloid pathway appeared not to be directly implicated in this effect, since: d(+)amphetamine application in the ACE, which enhanced the local release of DA, remained without effect on Met-IR release and haloperidol-induced blockade of dopaminergic receptors in the ACE similarly did not affect Met-IR release.
D000679:Amygdala / Q000187:drug effects / Q000378:metabolism*; D000818:Animals; D004744:Enkephalin, Methionine / Q000378:metabolism*; D008297:Male; D009434:Neural Pathways / Q000187:drug effects; D011188:Potassium / Q000494:pharmacology*; D011480:Protease Inhibitors / Q000494:pharmacology; D011863:Radioimmunoassay; D051381:Rats; D011919:Rats, Inbred Strains; D011954:Receptors, Dopamine / Q000187:drug effects / Q000502:physiology; D013378:Substantia Nigra / Q000187:drug effects
D011480:Protease Inhibitors; D011954:Receptors, Dopamine; D004744:Enkephalin, Methionine; D011188:Potassium