Role of 5-HT2A/C receptors in serotonergic modulation of respiratory motor output during tadpole development.
We tested the hypothesis that 5-HT(2A/C) receptors contribute to the modulation of respiratory motor output elicited by serotonin bath-application in the in vitro brainstem preparation from bullfrog tadpoles. Preparations were superfused with (1) a selective 5-HT(2A/C) receptor agonist (DOI, 0.5-25 microM) or (2) 5-HT in presence of a non-selective 5-HT(2A/C) receptor antagonist (methysergide maleate, 10 microM). Stage-related differences in 5-HT(2A/C) modulation were assessed by performing experiments on two groups: pre- and post-metamorphic tadpoles. 5-HT(2A/C) receptor activation with DOI did not alter either gill or lung burst frequency. Methysergide did not prevent the gill burst frequency attenuation elicited by 5-HT. Our results show no apparent contribution of the 5-HT(2A/C) receptor subtypes to the serotonergic modulation of either gill- or lung-related neural activity in either group. While 5-HT(2A/C) receptors are involved in the modulation of respiratory motor output in mammals, these receptor subtypes do not appear to play a significant role in this species.
Belzile
Olivier
O
Department of Pediatrics, Laval University, Centre de Recherche (D0-711) Hôpital St-François d'Assise, 10 rue de l'Espinay, Québec City, Québec, Canada G1L 3L5. slash1965@hotmail.com
Gulemetova
Roumiana
R
Kinkead
Richard
R
D000662:Amphetamines / Q000494:pharmacology; D000818:Animals; D001933:Brain Stem / Q000187:drug effects / Q000254:growth & development / Q000502:physiology*; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D005260:Female; D005880:Gills / Q000187:drug effects / Q000502:physiology; D066298:In Vitro Techniques; D007814:Larva / Q000254:growth & development*; D008168:Lung / Q000187:drug effects / Q000502:physiology*; D008297:Male; D008675:Metamorphosis, Biological; D008784:Methysergide / Q000494:pharmacology; D009474:Neurons / Q000187:drug effects / Q000502:physiology; D011892:Rana catesbeiana; D044402:Receptor, Serotonin, 5-HT2A; D044405:Receptor, Serotonin, 5-HT2C; D011985:Receptors, Serotonin / Q000502:physiology*; D015656:Respiratory Mechanics / Q000187:drug effects / Q000502:physiology; D012702:Serotonin Antagonists / Q000494:pharmacology; D017366:Serotonin Receptor Agonists / Q000494:pharmacology
D000662:Amphetamines; D044402:Receptor, Serotonin, 5-HT2A; D044405:Receptor, Serotonin, 5-HT2C; D011985:Receptors, Serotonin; D012702:Serotonin Antagonists; D017366:Serotonin Receptor Agonists; C015952:4-iodo-2,5-dimethoxyphenylisopropylamine; D008784:Methysergide