The effect of chronic treatment with imipramine on the G proteins mRNA level in the rat hippocampus--an interaction with a calcium channel antagonist.
The effect of long-term administration of imipramine (10 mg/kg po, twice daily, 30 days) with or without nifedipine (5 mg/kg ip, twice daily, 28 days) on the G protein alpha subunit, Gs alpha, Go alpha and Gi alpha mRNA levels was investigated in the rat hippocampus. An in situ hybridization histochemistry showed that imipramine decreased the Go alpha mRNA level in CA1 (by ca. 40%) and CA3 (by ca. 37%) hippocampal fields and, to a lesser extent, in the dentate gyrus (by ca. 25%), but had no effect on the Gs alpha and Gi alpha mRNA levels in those structures. Nifedipine decreased (by ca. 30%) the Gs alpha level in the studied fields of hippocampal formation, having no influence on the level of mRNA which codes other subunits of G protein. Coadministration of nifedipine and imipramine reversed the imipramine effect on Go alpha, but had no effect on the nifedipine-induced decrease at the Gs alpha mRNA level. These results suggest that inhibition of L calcium channels modifies the effect of imipramine at the level of intracellular signal transduction.
Lasoń
W
W
Neuropeptide Research Department, Polish Academy of Sciences, Kraków.
Przewłocki
R
R
D000818:Animals; D019204:GTP-Binding Proteins / Q000235:genetics*; D006624:Hippocampus / Q000187:drug effects* / Q000378:metabolism; D007099:Imipramine / Q000494:pharmacology*; D008297:Male; D009543:Nifedipine / Q000494:pharmacology*; D012333:RNA, Messenger / Q000032:analysis* / Q000235:genetics; D051381:Rats; D017208:Rats, Wistar; D011985:Receptors, Serotonin / Q000502:physiology
D012333:RNA, Messenger; D011985:Receptors, Serotonin; D019204:GTP-Binding Proteins; D009543:Nifedipine; D007099:Imipramine