glass micropipette recording electrode od, id, 8250 capillary glass  (Precision Glass Products)

Journal: American Journal of Physiology - Regulatory, Integrative and Comparative Physiology

Article Title: Hydrogen peroxide inhibits neurons in the paraventricular nucleus of the hypothalamus via potassium channel activation

doi: 10.1152/ajpregu.00054.2019

Figure Lengend Snippet: H2O2 hyperpolarizes paraventricular nucleus (PVN) neurons. A: an in vitro PVN slice with the recording electrode on the neuron (inset). F, fornix; OT, optic tract; 3V, third ventricle. Dashed line represents PVN region; smaller inset shows area of recording. B: morphology of 4 neurons reconstructed following recording. Scale bars = 20 μm. C: representative trace of spontaneous synaptic activity and holding current in artificial cerebrospinal fluid (aCSF) and H2O2. Note outward current in response to H2O2. Cell was voltage-clamped at −60 mV. D: group data showing holding current (Ihold) in aCSF, H2O2, and wash. Ihold was significantly greater in H2O2 than aCSF (baseline). E: H2O2 did not alter root mean square (RMS) noise. F: membrane potential (Vm), measured in current (I) clamp (I = 0), reversibly hyperpolarized following H2O2 application. *P < 0.05 vs. aCSF (by 1-way repeated-measures ANOVA with Fisher’s least significant difference test).

Article Snippet: Glass recording electrodes (3.5–5.0 MΩ; 8250, King Precision Glass, Claremont, CA) were filled with a solution containing (in mM) 10 NaCl, 130 K-gluconate, 11 EGTA, 1 CaCl 2 , 10 HEPES, 1 MgCl 2 , 2 MgATP, and 0.2 NaGTP (pH 7.3, 295–300 mosM).

Techniques: In Vitro, Activity Assay, Membrane

Journal: American Journal of Physiology - Regulatory, Integrative and Comparative Physiology

Article Title: Hydrogen peroxide inhibits neurons in the paraventricular nucleus of the hypothalamus via potassium channel activation

doi: 10.1152/ajpregu.00054.2019

Figure Lengend Snippet: H2O2 increases K+ currents (IK) at voltages near resting potential. A: voltage ramps in the absence and presence of H2O2 (red). H2O2 induced an upward shift in holding current (Ihold; B) and did not alter slope conductance (Gslope; C) but enhanced transient outward IK (D-E). Subtracted current is shown below traces. B–E: quantification of parameters highlighted in A during exposure to H2O2 alone and following 1 or more blockers. B: magnitude of change in Ihold before voltage ramps was reduced compared with H2O2 alone by exogenous catalase (Cat), diazoxide (Diaz), and Cs+-based electrodes. C: magnitude of change in Gslope during voltage ramps, as measured between −110 and −50 mV, was not altered by H2O2 alone or with various treatments. D and E: H2O2 increases an outward IK, enhancing the peak amplitude (D) and area (E) between −50 and −40 mV. Outward IK was eliminated by catalase and K+ channel modifiers. For C–E, 1 = no change in H2O2 from its baseline (BSL). *P < 0.05, H2O2 vs. preceding individual baseline (by paired t-test); #P < 0.05, H2O2 in treatment vs. H2O2 only (by 1-way ANOVA with Fisher’s least significant difference test).

Article Snippet: Glass recording electrodes (3.5–5.0 MΩ; 8250, King Precision Glass, Claremont, CA) were filled with a solution containing (in mM) 10 NaCl, 130 K-gluconate, 11 EGTA, 1 CaCl 2 , 10 HEPES, 1 MgCl 2 , 2 MgATP, and 0.2 NaGTP (pH 7.3, 295–300 mosM).

Techniques: