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. 1996 Jun 15;493(Pt 3):747–754. doi: 10.1113/jphysiol.1996.sp021419

Calcium-dependent prepotentials contribute to spontaneous activity in rat tuberomammillary neurons.

D R Stevens 1, H L Haas 1
PMCID: PMC1159022  PMID: 8799896

Abstract

1. Intracellular recordings from histaminergic neurons of the tuberomammillary (TM) nucleus reveal subthreshold depolarizing potentials (DPs) which persist in the presence of tetrodotoxin. 2. Block of hyperpolarization-activated current by 1-4 mM Cs+ failed to reduce spontaneous activity or DPs. 3. In the presence of tetrodotoxin DPs are voltage dependent and are depressed by Cd2+ and Co2+. 4. Ba2+ (100 microM) treatment enhances DP amplitude and converts low-amplitude potentials to tetrodotoxin-insensitive action potentials. 5. In the presence of TTX, DPs are reduced by Ni2+. Spontaneous action potentials are also reduced by Ni2+ (100-300 microM). A low-threshold Ca2+ current is present which is sensitive to Ni2+. These results indicate the presence of calcium currents, perhaps of the low-threshold type, which contribute to activation of action potentials in TM neurons.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

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