Serotonergic inhibition of phrenic motoneuron activity: an in vitro study in neonatal rat.
In vitro experiments were conducted on neonatal rat brainstem-spinal cord preparations to test the hypothesis of an inhibitory modulation of phrenic activity by serotonin (5-HT) via non-5-HT2A receptors [Lindsay, A.D. and Feldman, J.L., Modulation of respiratory activity of neonatal rat phrenic motoneurones by serotonin, J. Physiol., 461 (1993) 213-233]. The changes induced by 5-HT and related agents on phrenic root discharges and membrane currents in identified phrenic motoneurons were analysed after blockade of spinal 5-HT2A receptors. Spinal application of 5-HT1B (but not 5-HT1A) receptor agonists depressed the phrenic activity and the effect was prevented by pretreatment with 5-HT1B (but not 5-HT1A, 5-HT2A and 5-HT3) receptor antagonists. Results from phrenic motoneuron whole cell recordings do not reject a presynaptic location of the 5-HT receptors responsible for this depression.
Di Pasquale
E
E
UPRESA CNRS 6034, Biologie des Rythmes et du Développement, Faculté des Sciences de St Jérôme, Marseille, France.
Lindsay
A
A
Feldman
J
J
Monteau
R
R
Hilaire
G
G
D000200:Action Potentials / Q000502:physiology; D000818:Animals; D000831:Animals, Newborn; D001933:Brain Stem / Q000502:physiology*; D066298:In Vitro Techniques; D007211:Indoles / Q000494:pharmacology; D009046:Motor Neurons / Q000187:drug effects / Q000502:physiology*; D010791:Phrenic Nerve / Q000502:physiology*; D051381:Rats; D011985:Receptors, Serotonin / Q000502:physiology; D012701:Serotonin / Q000494:pharmacology*; D017366:Serotonin Receptor Agonists / Q000494:pharmacology; D013116:Spinal Cord / Q000502:physiology*; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology
D007211:Indoles; D011985:Receptors, Serotonin; D017366:Serotonin Receptor Agonists; C025145:5-methoxy 3-(1,2,3,6-tetrahydro-4-pyridinyl)1H indole; D012701:Serotonin