Hydrogen sulfide has reproducible responses and effects the various cell types in a similar manner.

<p>a) Current clamp recording trace illustrating a PVN neuron's rapid and repeatable response and recovery to 1 mM NaHS. Trace b) shows various concentrations (10 mM, 1 mM, and 0.1 mM) applied in the same neuron.</p

Hydrogen sulfide depolarizes PVN neurons.

<p>Traces illustrate the depolarizing effects of NaHS application on PVN neurons. a) Current clamp recording trace illustrating a depolarizing response to 1 mM NaHS. Trace b) shows a current clamp recording illustrating a depolarizing response to 10 mM NaHS. Bar graph c) illustrates the various responses to NaHS (0.1–50 mM) of PVN neurons (80%, n = 52/65 depolarized, 20%, n = 13/65 showed no response, and 3%, n = 2/65 hyperpolarized). Bar graph d) shows the percentage of PA (73%, n = 24/33), MNC (80%, n = 12/15), and NE (79%, n = 11/14) neurons that depolarized.</p

Hydrogen sulfide-induced depolarization is biphasic.

<p>a) Current clamp recording trace illustrating the change in input resistance over the duration of the hydrogen sulfide-induced depolarization (50 mM). b) V/I plot showing the change in input resistance (point of intercept, 114 mV), during the initial phase of the depolarization. c) V/I plot showing the change in input resistance (point of intercept, 62 mV), during the recovery phase of the depolarization. Input resistance calculated from the slope of the line.</p

Hydrogen sulfide has a concentration dependent relationship.

<p>Traces illustrate the magnitude of the depolarizations in response to the various NaHS concentrations (0.1, 1, 10, and 50 mM). As the concentrations increase so does the response. a) Current clamp recording trace illustrating no response to 0.1 mM NaHS. b) Current clamp recording trace illustrating a depolarizing response to 1 mM NaHS. c) Current clamp recording trace illustrating a depolarizing response to 10 mM NaHS. d) Current clamp recording trace illustrating a depolarizing response to 50 mM NaHS, with an increase in firing frequency during the initial phase of the depolarization. e) Scatter plot showing the response of all recorded neurons to the various NaHS concentrations (0.1, 1, 10, and 50 mM) with the mean response and standard deviations indicated by the black square and bars.</p

H2S SFO Data Analysis

Data summarizing every recording for current clamp and rheobase analyse

miSFOH2S for plos paper

Raw data for blood pressure recording

Hydrogen sulfide depolarizes neurons in a concentration-dependent manner.

<p>(A) Current clamp recording illustrating the concentration dependent effects of 4 different concentrations of NaHS (red bars indicate time of application) in a single SFO neuron. (B) Scatter plot indicating the membrane potential changes for all neurons recorded. Black bars indicate mean ± SEM. (C) NaHS concentration curve illustrating proportion of responding neurons at each concentration, EC₅₀ = 35.6 µM.</p

Hydrogen sulfide increases the excitability of SFO neurons.

<p>An analysis of rheobase and action potential firing frequency revealed an increase in excitability. (A) Current clamp trace with red bar indicating application of NaHS (1 mM), and blue bars (α and β) indicate periods when current injection protocol was performed. (B) The middle panel shows the current injection protocols for 2X and 3X rheobase steps, and 0–200 and 0–500 pA ramps, while the spike patterns induced are shown for the control (left panel, α) and NaHS (right panel, β) conditions. Bar graphs displaying the mean number of action potentials before (black) and during (grey) NaHS application for the current step (C) and ramp (D) protocols. Note the increase in action potential number in response to NaHS in all 4 cases. *p<0.05, paired t test.</p

Primer sets used for RT-PCR analysis.

<p>Primer sets used for RT-PCR analysis.</p

Hydrogen sulfide depolarizes SFO neurons.

<p>Current clamp recordings from 2 SFO neurons demonstrating depolarizing effects of 1 mM NaHS (red bars indicate time of application). There was no difference in the depolarizing response observed in neurons that (A) fired spontaneously or (B) cells that were quiescent. In both cases there is a rapid-onset depolarization, followed by a recovery to baseline after return to vehicle aCSF.</p