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Postnatal development of serotonin 1B, 2 A and 2C receptors in brainstem motoneurons
Author(s) -
Volgin Denys V.,
Fay Richard,
Kubin Leszek
Publication year - 2003
Publication title -
european journal of neuroscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.346
H-Index - 206
eISSN - 1460-9568
pISSN - 0953-816X
DOI - 10.1046/j.1460-9568.2003.02545.x
Subject(s) - receptor , brainstem , 5 ht receptor , serotonin , biology , messenger rna , neuroscience , endocrinology , medicine , inhibitory postsynaptic potential , microbiology and biotechnology , gene , biochemistry
The effects of serotonin (5‐HT) on motoneurons are mediated via multiple receptor subtypes. In hypoglossal (XII) motoneurons, the prototypic brainstem motoneurons whose functions change during the postnatal period, 5‐HT effects evolve from inhibitory to excitatory, probably in association with changes in receptor expression. We studied 5‐HT 1B , 5‐HT 2A and 5‐HT 2C receptor mRNA in 414 dissociated XII motoneurons and 5‐HT 2A protein in the XII, facial and spinal cervical (C2‐3) motor nuclei. The percentage of motoneurons expressing distinct mRNAs varied with the postnatal age (P3‐33 days) and receptor subtype. Initially, 5‐HT 1B mRNA was present in 50–85% of cells, but on P14 its expression transiently decreased below 35%. 5‐HT 2A mRNA was present in nearly all cells after P6, but in less than 65% on P3‐5. Normal and/or short splice variants of the 5‐HT 2C mRNA were expressed in less than 20% of motoneurons on P3‐9, and in ∼ 35% thereafter. 5‐HT 1B and 5‐HT 2A mRNAs often were expressed in different cells during early and intermediate postnatal periods, whereas 5‐HT 2C mRNA never occurred alone. The 5‐HT 2A receptor protein level gradually increased through P15 in the XII and facial nuclei, with dendritic labelling appearing in XII motoneurons only after P12. In spinal motoneurons, both somatic and dendritic labelling was strongest on P5 and then decreased. The development of 5‐HT receptors in XII motoneurons may be related to changes in feeding behaviour, whereas different cues regulate 5‐HT receptor expression in upper spinal motoneurons.