Postnatal decrease of sodium current density in rat pituitary melanotropes following the onset of dopaminergic innervation.

L F López-Santiago; J C Gómora; G Cota

doi:10.1016/s0304-3940(01)02355-2

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Postnatal decrease of sodium current density in rat pituitary melanotropes following the onset of dopaminergic innervation.

L F López-Santiago·J C Gómora·G Cota

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Abstract

Peptide secretion from rat melanotropes is tonically inhibited by a dopaminergic synaptic input that develops after birth and acts through D2 dopamine receptors. In this study, whole-cell Na(+) currents were recorded from melanotropes that were isolated from rat pituitary intermediate lobes at postnatal days 1-20 (P1-P20) and maintained in culture for 5-24 h. Coincident with the development of innervation, melanotropes exhibited a progressive decrease in peak Na(+) current density from P3 to P14. The decrease involved a 50% reduction in maximal Na(+) conductance with no detectable changes in channel gating. Subcutaneous injections of the D2 antagonist sulpiride, applied from P11 to P13, restored melanotrope Na(+) channel activity to pre-innervation levels. Thus, the activation of D2 receptors by the dopaminergic input reduces the functional expression of Na(+) channels in melanotropes.

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Aging Animals Animals, Newborn Cells, Cultured Dopamine Electric Conductivity Melanocyte-Stimulating Hormones Pituitary Gland Rats Rats, Wistar Sodium Channels Journal Article Research Support, Non-U.S. Gov't

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L F López-Santiago, J C Gómora, G Cota. 2001-11-27. Postnatal decrease of sodium current density in rat pituitary melanotropes following the onset of dopaminergic innervation.. https://doi.org/10.1016/s0304-3940(01)02355-2

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