Leptin modulates fast synaptic transmission in dog pancreatic ganglia.
The aim of this study was to determine whether leptin modulates neuronal activity in intrapancreatic ganglion neurons. Intracellular recordings were made in dog pancreatic neurons. Recombinant mouse leptin (313 nM) was added by superfusion. When leptin was present, fast EPSPs which were subthreshold in normal Krebs solution reached threshold for firing action potentials. However, leptin had no significant (P > 0.05, n = 18) effect on either the resting membrane potential or on membrane input resistance. To determine whether leptin increased the postsynaptic sensitivity to acetylcholine, the response was tested by pressure ejection of acetylcholine. Acetylcholine evoked a 9.4+/-2.2 mV (mean +/- SEM, n = 5) depolarization in normal Krebs solution. In the presence of leptin, the response was not significantly different (9.6+/-2.4 mV, P > 0.05). The results suggest that leptin modulates fast synaptic transmission in pancreatic ganglion neurons by acting on presynaptic nerve terminals.
Sha
L
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Department of Physiology and Biophysics, Mayo Clinic and Mayo Foundation, Rochester, MN 55905, USA.
Szurszewski
J H
JH
D000109:Acetylcholine / Q000494:pharmacology; D000200:Action Potentials / Q000187:drug effects / Q000502:physiology; D000273:Adipose Tissue; D000818:Animals; D004285:Dogs; D004558:Electric Stimulation; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects / Q000502:physiology*; D005724:Ganglia; D005725:Ganglia, Autonomic / Q000187:drug effects / Q000502:physiology*; D020738:Leptin; D051379:Mice; D009474:Neurons / Q000187:drug effects / Q000502:physiology*; D010179:Pancreas / Q000294:innervation*; D011506:Proteins / Q000494:pharmacology*; D011994:Recombinant Proteins / Q000494:pharmacology; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology*
D020738:Leptin; D011506:Proteins; D011994:Recombinant Proteins; D000109:Acetylcholine