H.-P.Z. and Z.-Y.X. contributed equally to this work.
Bombesin facilitates GABAergic transmission and depresses epileptiform activity in the entorhinal cortex
Version of Record online: 14 SEP 2013
Copyright © 2013 Wiley Periodicals, Inc.
Volume 24, Issue 1, pages 21–31, January 2014
How to Cite
Zhang, H.-p., Xiao, Z., Cilz, N. I., Hu, B., Dong, H. and Lei, S. (2014), Bombesin facilitates GABAergic transmission and depresses epileptiform activity in the entorhinal cortex. Hippocampus, 24: 21–31. doi: 10.1002/hipo.22191
- Issue online: 10 DEC 2013
- Version of Record online: 14 SEP 2013
- Accepted manuscript online: 22 AUG 2013 04:49AM EST
- Manuscript Accepted: 13 AUG 2013
- Manuscript Revised: 6 AUG 2013
- Manuscript Received: 28 MAY 2013
- NIH, National Natural Science Foundation of China. Grant Numbers: R01MH082881, 81128005
- synaptic transmission;
- K+ channels;
- action potential
Bombesin and the bombesin-like peptides including neuromedin B (NMB) and gastrin-releasing peptide (GRP) are important neuromodulators in the brain. We studied their effects on GABAergic transmission and epileptiform activity in the entorhinal cortex (EC). Bath application of bombesin concentration-dependently increased both the frequency and amplitude of sIPSCs recorded from the principal neurons in the EC. Application of NMB and GRP exerted the same effects as bombesin. Bombesin had no effects on mIPSCs recorded in the presence of TTX but slightly depressed the evoked IPSCs. Omission of extracellular Ca2+ or inclusion of voltage-gated Ca2+ channel blockers, Cd2+ and Ni2+, blocked bombesin-induced increases in sIPSCs suggesting that bombesin increases GABA release via facilitating extracellular Ca2+ influx. Bombesin induced membrane depolarization and slightly increased the input resistance of GABAergic interneurons recorded from layer III of the EC. The action potential firing frequency of the interneurons was also increased by bombesin. Bombesin-mediated depolarization of interneurons was unlikely to be mediated by the opening of a cationic conductance but due to the inhibition of inward rectifier K+ channels. Bath application of bombesin, NMB and GRP depressed the frequency of the epileptiform activity elicited by deprivation of Mg2+ from the extracellular solution suggesting that bombesin and the bombesin-like peptides have antiepileptic effects in the brain. © 2013 Wiley Periodicals, Inc.