Delayed rectification was elicited in frog's skeletal muscles bathed in choline-Ringer's solution, in normal Ringer's solution with tetrodotoxin, in 40 mM Na(2)SO(4) solution with tetrodotoxin, and even in 40 mM K(2)SO(4) solution when the membrane had been previously hyperpolarized. However, after a sustained depolarization current-voltage relations in 40 mM K(2)SO(4) and in 40 mM Na(2)SO(4) s...

Early events in NaCl-induced root ion and water transport were investigated in maize (Zea mays L) roots using a range of microelectrode and imaging techniques. Addition of 100 mm NaCl to the bath resulted in an exponential drop in root xylem pressure, rapid depolarization of trans-root potential and a transient drop in xylem K(+) activity (A(K+) ) within ∼1 min after stress onset. At this time,...

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main source(s): TED2021-130459B-I00 LMP94_21 Introduction Left bundle branch area pacing (LBBAP) has been recently proposed to overcome the limitations associated with right ventricular (RVP) and suggested as a new physiological form high feasibility safety. A greater difference between QRS comple...

Intracellular recordings were made from rat hippocampal CA1 neurons in rat brain slice preparations to investigate whether cAMP-dependent protein kinase (PKA) and calcium/phospholipid-dependent protein kinase C (PKC) contribute to the membrane dysfunction induced by oxygen and glucose deprivation (OGD). Superfusion of oxygen- and glucose-deprived medium produced a rapid depolarization ∼5 min af...

GABA release during cerebral energy deprivation (produced by anoxia or ischemia) has been suggested either to be neuroprotective, because GABA will hyperpolarize neurons and reduce release of excitotoxic glutamate, or to be neurotoxic, because activation of GABA(A) receptors facilitates Cl- entry into neurons and consequent cell swelling. We have used the GABA(A) receptors of hippocampal area C...

Synaptic function and plasticity are crucial for information processing within the nervous system. In glutamatergic hippocampal neurons, presynaptic function is silenced, or muted, after strong or prolonged depolarization. This muting is neuroprotective, but the underlying mechanisms responsible for muting and its reversal, unmuting, remain to be clarified. Using cultured rat hippocampal neuron...

To maintain horizontal eye position on a visual target after a saccade, extraocular motoneurons need a persistent (tonic) neural activity, called "eye-position signal," generated by prepositus hypoglossi (PH) neurons. We have shown previously in vitro and in vivo that this neural activity depends, among others mechanisms, on the interplay of glutamatergic transmission and cholinergic synaptical...

BACKGROUND Ischemia-reperfusion (I/R) studies have implicated oxidant stress, the mitochondrial permeability transition pore (mPTP), and poly(ADP-ribose) polymerase (PARP) as contributing factors in myocardial cell death. However, the interdependence of these factors in the intact, blood-perfused heart is not known. We therefore wanted to determine whether oxidant stress, mPTP opening, and PARP...

In many neurons, strong excitatory stimulation causes an after-hyperpolarization (AHP) at stimulus offset, which might give rise to activity-dependent adaptation. Graded-potential visual motion-sensitive neurons of the fly Calliphora vicina respond with depolarization and hyperpolarization during motion in their preferred direction and their anti-preferred direction, respectively. A prominent a...

Despite the lack of direct evidence, it is generally believed that top-down signals are mediated by the abundant feedback connections from higher- to lower-order sensory areas. Here we provide direct evidence for a top-down mechanism. We stained the visual cortex of the ferret with a voltage-sensitive dye and presented a short-duration contrast square. This elicited an initial feedforward and l...