Activation of 5HT1B receptors inhibits glycinergic synaptic inputs to mammalian motoneurons during postnatal development.
We investigated whether 5-HT(1B) receptor-mediated inhibition of evoked glycinergic inhibitory postsynaptic currents (eIPSCs) in hypoglossal motoneurons (HMs) changed postnatally. In HMs from postnatal days 2-3 (P2-3, neonate) and P10-11 (juvenile) rats bath application of 5-HT (10 microM) caused a not significantly different large reduction in eIPSC amplitude to 35.0+/-22.5% (mean+/-S.D.) and 35.4+/-10.6% of control; respectively. The dose-response relationship for the 5-HT(1B) receptor agonist, CP-93,129, revealed that the mean agonist concentration at half-maximal inhibition (IC(50)) was similar, 1.6 and 2.0 nM, respectively. Additionally, strong antibody labeling of 5-HT(1B) receptors in the hypoglossal motor nucleus was observed in neonates, juveniles and adults. These results demonstrate that over the postnatal period studied, 5-HT(1B) receptor-mediated inhibition of glycinergic eIPSCs is not age dependent.
Berger
Albert J
AJ
Department of Physiology and Biophysics, School of Medicine, University of Washington, Box 357290, Seattle, WA 98195-7290, USA. berger@u.washington.edu
Huynh
Phan
P
D000818:Animals; D000831:Animals, Newborn; D004305:Dose-Response Relationship, Drug; D005998:Glycine / Q000378:metabolism*; D018684:Glycine Agents / Q000494:pharmacology; D007002:Hypoglossal Nerve / Q000187:drug effects / Q000254:growth & development*; D009046:Motor Neurons / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D009433:Neural Inhibition / Q000187:drug effects; D018408:Patch-Clamp Techniques; D011725:Pyridines / Q000494:pharmacology; D011758:Pyrroles / Q000494:pharmacology; D051381:Rats; D044302:Receptor, Serotonin, 5-HT1B; D011985:Receptors, Serotonin / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D017366:Serotonin Receptor Agonists / Q000494:pharmacology; D013331:Strychnine / Q000494:pharmacology; D009435:Synaptic Transmission / Q000187:drug effects
D018684:Glycine Agents; D011725:Pyridines; D011758:Pyrroles; D044302:Receptor, Serotonin, 5-HT1B; D011985:Receptors, Serotonin; D017366:Serotonin Receptor Agonists; C065046:3-(1,2,5,6-tetrahydropyrid-4-yl)pyrrolo(3,2-b)pyrid-5-one; D013331:Strychnine; D005998:Glycine