Glucagon-like peptide-1 modulates synaptic transmission to identified pancreas-projecting vagal motoneurons.
Using a brainstem slice preparation, we aimed to study the pre- and postsynaptic effects of glucagon-like peptide-1 (GLP-1) on synaptic transmission to identified pancreas-projecting vagal motoneurons. Following blockade of GABAergic mediated currents with bicuculline, perfusion with 100 nM GLP-1 increased both amplitude and frequency of excitatory postsynaptic currents (EPSCs) in 21 of 52 neurons. Perfusion with the GLP-1 selective agonist exendin-4 (100 nM), also increased the frequency of spontaneous EPSCs, while pretreatment with the GLP-1 selective antagonist, exendin 9-39, prevented the effects of GLP-1. In the presence of kynurenic acid to block ionotropic glutamatergic currents, perfusion with GLP-1 increased the frequency of inhibitory postsynaptic currents (IPSCs) in 28 of 74 neurons; in 14 of these responsive neurons, GLP-1 also increased IPSC amplitude, indicating actions at both pre- and postsynaptic sites. Perfusion with exendin-4 increased the frequency of spontaneous IPSCs, while pretreatment with exendin 9-39 prevented the effects of GLP-1. These results suggest that GLP-1 modulates both excitatory and inhibitory synaptic inputs to pancreas-projecting vagal motoneurons.
Wan
Shuxia
S
Research Center of Digestive Diseases, Zhongnan Hospital, Key Laboratory of Allergy and Immune-related Diseases, Department of Physiology, School of Basic Medical Science, Wuhan University, Wuhan, Hubei 430071, PR China.
Browning
Kirsteen N
KN
Travagli
R Alberto
RA
D000818:Animals; D001933:Brain Stem / Q000187:drug effects / Q000502:physiology; D004594:Electrophysiology; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects; D052216:Glucagon-Like Peptide 1 / Q000494:pharmacology*; D053444:Inhibitory Postsynaptic Potentials / Q000187:drug effects; D007736:Kynurenic Acid / Q000494:pharmacology; D009046:Motor Neurons / Q000187:drug effects / Q000502:physiology; D010179:Pancreas / Q000166:cytology / Q000187:drug effects* / Q000294:innervation; D018408:Patch-Clamp Techniques; D010446:Peptide Fragments / Q000494:pharmacology; D051381:Rats; D009435:Synaptic Transmission / Q000187:drug effects*; D014630:Vagus Nerve / Q000166:cytology / Q000187:drug effects / Q000502:physiology
D010446:Peptide Fragments; C083773:exendin (9-39); D052216:Glucagon-Like Peptide 1; D007736:Kynurenic Acid