c-Fos proteins, induced by the serotonin receptor agonist DOI, are not expressed in 5-HT2A positive cortical neurons.
In the present study, we tried to find out whether the expression of c-Fos proteins induced by DOI, an agonist of 5-HT2A/2C receptor subtypes is colocalized with 5-HT2A receptor protein in cortical neurons. 5-HT2A receptor protein was found in two major neuronal elements: dendritic processes (seen in layers II/III-V) and less abundantly in cell bodies (layer V). In our experiment, DOI (8 mg/kg) induced a robust appearance of c-Fos proteins mainly in neuronal nuclei of the upper part of layer V/IV, and a moderate amount of sparsely distributed nuclei in deep cortical layers (V and VI). It was found that c-Fos proteins never occurred in cortical neurons, which were immunopositive for the presence of 5-HT2A receptor protein. It is concluded that the induction of c-Fos proteins expression by DOI though initiated by activation of 5-HT2A receptors, requires the involvement of intermediate neurotransmitter(s). Additionally, our study indicates that the appearance of DOI-induced c-Fos proteins cannot be used as a simple and direct marker of localization and site of activation of 5-HT2A receptors.
Maćkowiak
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M
Institute of Pharmacology, Polish Academy of Sciences, 31-343, Kraków, Poland.
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Fijał
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D000662:Amphetamines / Q000494:pharmacology*; D000818:Animals; D002540:Cerebral Cortex / Q000166:cytology / Q000378:metabolism*; D008297:Male; D008970:Molecular Weight; D009474:Neurons / Q000378:metabolism*; D016760:Proto-Oncogene Proteins c-fos / Q000096:biosynthesis*; D051381:Rats; D017208:Rats, Wistar; D044402:Receptor, Serotonin, 5-HT2A; D044405:Receptor, Serotonin, 5-HT2C; D011985:Receptors, Serotonin / Q000378:metabolism*; D017366:Serotonin Receptor Agonists / Q000494:pharmacology*
D000662:Amphetamines; D016760:Proto-Oncogene Proteins c-fos; D044402:Receptor, Serotonin, 5-HT2A; D044405:Receptor, Serotonin, 5-HT2C; D011985:Receptors, Serotonin; D017366:Serotonin Receptor Agonists; C015952:4-iodo-2,5-dimethoxyphenylisopropylamine