Fig 3.
(3β,5β,17β)-3-hydroxyandrostane-17-carbonitrile blocks T-type calcium currents (T-currents) in subicular neurones. (a) Original T-current traces from a representative subicular neurone at baseline (black trace) and after application of (3β,5β,17β)-3-hydroxyandrostane-17-carbonitrile (3β-OH) 1 μM (red trace), generated using a double-pulse protocol with three different 3.6-s prepulses: −110 mV (left), −100 mV (middle), and −90 mV (right). (b) Average current amplitudes exhibit a significant decrease after the application of 3β-OH 1 μM across different conditioning potentials. The inset shows the chemical structure of 3β-OH, a neuroactive steroid analogue based on a progesterone scaffold with OH and CN groups in a beta-conformation at positions 3 and 17, respectively. (c) Steady-state inactivation curves (I/Imax) display a leftward shift upon the application of 3β-OH. Inset shows original traces from a representative subicular neurone at baseline (black trace) and after 3β-OH (red trace), generated using our standard steady-state inactivation protocol. Results are expressed as mean (standard error of mean). *P<0.05, †P<0.01, and ‡P<0.001, two-way repeated measures analysis of variance followed by Holm-Sidak's post hoc test.