Acid-sensing ion channels (ASICs) play an important role in numerous functions in the central and peripheral nervous systems ranging from memory and emotions to pain. The data correspond to a recent notion that each neuron and many glial cells of the mammalian brain express at least one member of the ASIC family. However, the mechanisms underlying the involvement of ASICs in neuronal activity are poorly understood. However, there are two exceptions, namely, the straightforward role of ASICs in proton-based synaptic transmission in certain brain areas and the role of the Ca(2+)-permeable ASIC1a subtype in ischaemic cell death. Using a novel orthosteric ASIC antagonist, we have found that ASICs specifically control the frequency of spontaneous inhibitory synaptic activity in the hippocampus. Inhibition of ASICs leads to a strong increase in the frequency of spontaneous inhibitory postsynaptic currents. This effect is presynaptic because it is fully reproducible in single synaptic boutons attached to isolated hippocampal neurons. In concert with this observation, inhibition of the ASIC current diminishes epileptic discharges in a low Mg(2+) model of epilepsy in hippocampal slices and significantly reduces kainate-induced discharges in the hippocampus in vivo Our results reveal a significant novel role for ASICs.This article is part of the themed issue 'Evolution brings Ca(2+) and ATP together to control life and death'.

Diabetic kidney disease (DKD) is one of the leading pathological causes of decreased renal function and progression to end-stage kidney failure. To explore and characterize age-related changes in DKD and associated glomerular damage, we used a rat model of type 2 diabetic nephropathy (T2DN) at 12 wk and older than 48 wk. We compared their disease progression with control nondiabetic Wistar and diabetic Goto-Kakizaki (GK) rats. During the early stages of DKD, T2DN and GK animals revealed significant increases in blood glucose and kidney-to-body weight ratio. Both diabetic groups had significantly altered renin-angiotensin-aldosterone system function. Thereafter, during the later stages of disease progression, T2DN rats demonstrated a remarkable increase in renal damage compared with GK and Wistar rats, as indicated by renal hypertrophy, polyuria accompanied by a decrease in urine osmolarity, high cholesterol, a significant prevalence of medullary protein casts, and severe forms of glomerular injury. Urinary nephrin shedding indicated loss of the glomerular slit diaphragm, which also correlates with the dramatic elevation in albuminuria and loss of podocin staining in aged T2DN rats. Furthermore, we used scanning ion microscopy topographical analyses to detect and quantify the pathological remodeling in podocyte foot projections of isolated glomeruli from T2DN animals. In summary, T2DN rats developed renal and physiological abnormalities similar to clinical observations in human patients with DKD, including progressive glomerular damage and a significant decrease in renin-angiotensin-aldosterone system plasma levels, indicating these rats are an excellent model for studying the progression of renal damage in type 2 DKD.

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Our current knowledge of the properties of renal ion channels responsible for electrolytes and cell energy homeostasis mainly relies on rodent studies. However, it has not been established yet to what extent their characteristics can be generalized to those of humans. The present study was designed to develop a standardized protocol for the isolation of well-preserved glomeruli and renal tubules from rodent and human kidneys and to assess the functional suitability of the obtained materials for physiological studies. Separation of nephron segments from human and rodent kidneys was achieved using a novel vibrodissociation technique. The integrity of isolated renal tubules and glomeruli was probed via electrophysiological analysis and fluorescence microscopy, and the purity of the collected fractions was confirmed using quantitative RT-PCR with gene markers for specific cell types. The developed approach allows rapid isolation of well-preserved renal tubules and glomeruli from human and rodent kidneys amenable for electrophysiological, Ca2+ imaging, and omics studies. Analysis of the basic electrophysiological parameters of major K+ and Na+ channels expressed in human cortical collecting ducts revealed that they exhibited similar biophysical properties as previously reported in rodent studies. Using vibrodissociation for nephron segment isolation has several advantages over existing techniques: it is less labor intensive, requires little to no enzymatic treatment, and produces large quantities of well-preserved experimental material in pure fractions. Applying this method for the separation of nephron segments from human and rodent kidneys may be a powerful tool for the indepth assessment of kidney function in health and disease.

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У нашій роботі досліджено внесок протеазоактивованих рецепторів 1 (ПАР1) у модуляцію соціальної поведінки щурів з епілептичним статусом (ЕС). З використанням літій-пілокарпінової моделі ЕС та тесту «перегородка» показано значне зниження товариськості та інтересу до соціальної новизни у щурів на 14-й день після ЕС, що є характерним розладом, який супроводжує розвиток епілепсії, причому вони проводили значно менше часу (5,85 ± 1,11 % від загального часу в експериментальній камері) із «соціальним» подразником, ніж група контрольних тварин (15,04 ± 1,59 %). Вперше продемонстровано, що блокування ПАР1 не впливає на характеристики соціальної поведінки дослідних тварин як за контрольних умов, так і за умов моделювання ЕС, що свідчить про відсутність залучення цих рецепторів у механізми формування соціальної поведінки щурів. Ключові слова: протеазоактивовані рецептори 1; соціальна поведінка; епілептичний статус; літій-пілокарпінова модель.

The effect of pharmacological blockade of ASIC1a channels on emotionally conditioned learning in rats with lithiumpilocarpine model of temporal lobe epilepsy was studied. The development of status epilepticus is known to impair both contextual and stimulated emotional learning. In our experiments, the painful effect was directly accompanied by freezing in animals of all groups, however, under conditions of induced epilepsy, its duration was shorter, and blocking ASIC1a channels neutralized this difference. The induction of epilepsy disrupted both contextual and stimulated emotional learning. Suppression of ASIC1a channels partially restored this process in animals with induced epilepsy. This means that pharmacological blocking of ASIC1a channels can have a positive therapeutic effect in correcting the emotional disorders associated with temporal lobe epilepsy.