ISSN:
1432-2072
Keywords:
Key words Imipramine
;
Serotonin
;
Raphe nuclei
;
Prefrontal cortex
;
Microdialysis
;
Rat
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Abstract The effect of acute administrations of three doses of imipramine (1, 5 and 10 mg/kg SC), a widely used tricyclic antidepressant, on extracellular levels of serotonin (5-HT) has been studied by intracerebral microdialysis in raphe nuclei and prefrontal cortex of conscious rats. Imipramine 1 mg/kg SC did not change extracellular 5-HT in either raphe nuclei and prefrontal cortex. However, with the dose of 5 mg/kg SC imipramine induced in raphe nuclei, a brief increase of extracellular 5-HT followed by a lowering (55–65% basal release) of the neurotransmitter. The same dose of imipramine decreased (60–70% of basal value) extracellular 5-HT in prefrontal cortex. Imipramine 10 mg/kg SC significantly increased 5-HT levels in both raphe nuclei (190 ± 20% above basal value) and prefrontal cortex (280 ± 15% above basal value). Pretreatment with (-)pindolol (5 mg/kg SC), a non-selective 5-HT1A subtype receptor antagonist, 30 min before imipramine 5 mg/kg, modified the effect of the antidepressant: an increase, instead of a decrease, on prefrontal cortex dialysate 5-HT was observed. (-)Pindolol (10 mg/kg SC) increased extracellular 5-HT in both raphe nuclei (155 ± 20% above basal value) and prefrontal cortex (160 ± 8% above basal value). These data show that acute administration of imipramine modifies extracellular 5-HT at the level of the raphe nuclei and prefrontal cortex. 5-HT1A autoreceptors in the raphe nuclei, which this study suggests to be tonically active, may be stimulated after systemic administration of high doses of imipramine.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/s002130050477
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