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Acute and Chronic Treatments with Citalopram Lower Somatostatin Levels in Rat Brain Striatum Through Different Mechanisms
Author(s) -
Prosperini Elena,
Rizzi Massimo,
Fumagalli Fabio,
Tarizzo Gianluca,
Samanin Rosario,
Bendotti Caterina
Publication year - 1997
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1046/j.1471-4159.1997.69010206.x
Subject(s) - citalopram , somatostatin , striatum , nucleus accumbens , medicine , endocrinology , basal ganglia , serotonin , serotonin reuptake inhibitor , ventral striatum , hippocampus , neuropeptide , chemistry , pharmacology , central nervous system , dopamine , receptor
The suggestion that somatostatin is involved in the pathophysiology of obsessive‐compulsive disorder and the evidence that selective serotonin reuptake inhibitors show significant antiobsessional effect prompted us to examine the effect of citalopram, a selective and potent serotonin reuptake inhibitor, on the somatostatinergic system in different brain regions of the rat. A single intraperitoneal injection of 10 mg/kg citalopram significantly reduced somatostatin levels in the striatum and nucleus accumbens after 4 but not 1, 8, or 24 h. No changes were found in hippocampus. In addition, we found that the K + ‐evoked overflow of somatostatin‐like immunoreactivity from striatal slices was significantly increased 1 h after a single injection of citalopram and was still higher, although not significantly, 4 h after the drug injection. Levels of preprosomatostatin mRNA were unchanged in striatum and accumbens 1 and 4 h after a single drug administration. In rats treated with citalopram (10 mg/kg i.p.) twice daily for 14 days, the levels of somatostatin and its mRNA were significantly decreased in the striatum but not in other brain regions 24 h after the last dose. No change was found in the basal or K + ‐evoked overflow of somatostatin‐like immunoreactivity at 1, 4, and 24 h after the last drug injection. These results suggest that acute and chronic treatment with citalopram reduces somatostatin levels in striatum by different mechanisms. Whereas a single dose of the drug reduces somatostatin levels by increasing the release of the peptide, repeated drug treatment reduces the biosynthesis of somatostatin.