title: Differential contribution of BDNF and NGF to long-term potentiation in the superior cervical ganglion of the rat.
abstract: Synaptic transmission in the sympathetic nervous system is a plastic process modulated by different factors. We characterized the effects of brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF) on basal transmission and ganglionic long-term potentiation (LTP) in the rat superior cervical ganglion. LTP was elicited by supramaximal tetanic stimulation (40 Hz, 3 s) of the sympathetic trunk and was quantified by measuring LTP decay time and LTP extent. Neurotrophins did not affect basal transmission, however, they differentially affected LTP. BDNF (200 ng/ml) increased LTP decay time and LTP extent 2.0-fold (p < 0.01). In contrast, NGF showed a dual effect: 200 ng/ml NGF reduced LTP decay time and LTP extent to 53% and to 32% of control value (p < 0.0001 and p < 0.02; respectively), whereas >350 ng/ml NGF significantly increased LTP decay time and LTP extent (p < 0.02). Digital analysis of compound action potentials suggests that neurotrophins could change the synchronization of unitary action potentials. Pharmacological data obtained in intact ganglia show that C2-ceramide produced a 2-fold enhancement in LTP, whereas tyrphostin AG879, an inhibitor of tyrosine kinase activity, reversed the NGF blockade and produced by itself an enhancement in LTP. In sliced ganglia we observed that an anti-TrkA antibody reversed the NGF-induced LTP blockade. Immunohistochemistry studies revealed that 83% of ganglionic neurons express TrkA, whereas 52% express p75 receptor, and 18% express TrkB receptor. We propose that p75 neurotrophin receptors and probably TrkB signaling enhance LTP, whereas TrkA signaling reduces it.
authors: Departamento de Biología Celular & Fisiología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, 3er Circuito Exterior s/número, Cd. Universitaria, México, D.F. 04510, Mexico.
authors: Erwin R
authors: ER
authors: Arias
authors: Departamento de Biología Celular & Fisiología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, 3er Circuito Exterior s/número, Cd. Universitaria, México, D.F. 04510, Mexico.
authors: Pablo
authors: P
authors: Valle-Leija
authors: Departamento de Biología Celular & Fisiología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, 3er Circuito Exterior s/número, Cd. Universitaria, México, D.F. 04510, Mexico.
authors: Miguel A
authors: MA
authors: Morales
authors: Departamento de Biología Celular & Fisiología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, 3er Circuito Exterior s/número, Cd. Universitaria, México, D.F. 04510, Mexico. Electronic address: fcifuent@biomedicas.unam.mx.
authors: Fredy
authors: F
authors: Cifuentes
mesh_terms: D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D019208:Brain-Derived Neurotrophic Factor / Q000494:pharmacology*; D002518:Ceramides / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004558:Electric Stimulation; D017774:Long-Term Potentiation / Q000187:drug effects*; D008297:Male; D020932:Nerve Growth Factor / Q000378:metabolism / Q000494:pharmacology*; D009419:Nerve Tissue Proteins; D009474:Neurons / Q000187:drug effects*; D051381:Rats; D017208:Rats, Wistar; D020917:Receptor, trkA / Q000378:metabolism; D020813:Receptor, trkB / Q000378:metabolism; D017978:Receptors, Growth Factor; D017475:Receptors, Nerve Growth Factor / Q000378:metabolism; D017783:Superior Cervical Ganglion / Q000166:cytology*; D020032:Tyrphostins / Q000494:pharmacology
chemical_list: C081020:AG-879; D019208:Brain-Derived Neurotrophic Factor; D002518:Ceramides; D009419:Nerve Tissue Proteins; D017978:Receptors, Growth Factor; D017475:Receptors, Nerve Growth Factor; D020032:Tyrphostins; C068313:Ngfr protein, rat; D020932:Nerve Growth Factor; D020917:Receptor, trkA; D020813:Receptor, trkB
keywords: Latency; Neurotrophic factors; Sympathetic neurons; Synaptic plasticity; Trk; p75NTR