Neural excitability, synaptic transmission and neuron-glia interactions
Author: María Natalia Gobetto | Email: natygobetto@gmail.com
M. Natalia Gobetto1°, Francisco J. Urbano1°,Paula P. Perissinotti1°
1° IFIBYNE – CONICET- UBA
The Hyperpolarization-activated Cyclic Nucleotide-gated (HCN2/4) channel isoforms are abundantly expressed in the thalamus. The pivotal role of HCN channels arises from their ability to influence membrane properties such as resting membrane potential and input resistance, which are crucial for determining a neuron’s role within a circuit. Using the whole-cell patch-clamp technique, we observed a sexual dimorphism in the functional expression of the H current mediated by HCN channels in the somatosensory nucleus (ventrobasal, VB).
In this study, we further characterized the H current at different postnatal stages. We found that H current density increased by 30% in females between 25-30 and 35-60 postnatal days (n = 8, 12), while no changes were observed in males (n = 11, 12). Given that HCN channels are well known targets of various hormones and neuromodulators, this sexual dimorphism suggests a modulation by sex hormones. To investigate this, a group of female mice were ovariectomized at 20-25 days postnatally, and HCN current density was recorded at 50-60 days. No increase in HCN current was observed in ovariectomized compared to sham-operated females (sham: n = 7, ovariectomized: n = 11). We´ve also found that upregulation of H current density in the VB nucleus correlated with increased mechanical sensitivity in the von Frey behavioral test. Consequently, this test started to be performed on female mice at different stages of the estrous cycle, as well as on males.