Vasoactive intestinal polypeptide modulates neuronal excitability in hippocampal slices of the rat.
Vasoactive intestinal polypeptide added at submicromolar concentrations to the perfusion fluid of rat hippocampal slices and slice cultures enhanced the excitability of CA1 and CA3 pyramidal cells in several ways. Specifically, cells were depolarized and the Ca(2+)- and cyclic AMP-dependent potassium conductance was blocked as demonstrated by reduction of the long-lasting afterhyperpolarization and the accommodation of firing. This was also found in tetrodotoxin-containing medium. In low Ca(2+)-high Mg2+ medium (in synaptic isolation) the firing rate was increased. Synaptic transmission was potentiated: extracellularly registered excitatory postsynaptic potentials and population spikes in response to stratum radiatum stimulation and intracellularly recorded excitatory postsynaptic potential-inhibitory postsynaptic potential sequences were enhanced. These results are in keeping with the known stimulation of adenylate cyclase by vasoactive intestinal polypeptide.
Haas
H L
HL
Department of Physiology, Heinrich-Heine-University, Düsseldorf, F.R.G.
Gähwiler
B H
BH
D000818:Animals; D002118:Calcium / Q000502:physiology; D000242:Cyclic AMP / Q000378:metabolism; D004558:Electric Stimulation; D005071:Evoked Potentials / Q000502:physiology; D006624:Hippocampus / Q000502:physiology*; D066298:In Vitro Techniques; D008274:Magnesium / Q000502:physiology; D008564:Membrane Potentials / Q000502:physiology; D009474:Neurons / Q000502:physiology*; D015221:Potassium Channels / Q000187:drug effects; D051381:Rats; D011919:Rats, Inbred Strains; D013569:Synapses / Q000201:enzymology / Q000502:physiology; D013757:Tetraethylammonium Compounds / Q000494:pharmacology; D013779:Tetrodotoxin / Q000494:pharmacology; D014660:Vasoactive Intestinal Peptide / Q000502:physiology*
D015221:Potassium Channels; D013757:Tetraethylammonium Compounds; D014660:Vasoactive Intestinal Peptide; D013779:Tetrodotoxin; D000242:Cyclic AMP; D008274:Magnesium; D002118:Calcium