Role of protein kinase C in regulating smooth muscle electrical and contractile activity: the effect of phorbol ester

The effects of protein kinase C activation by 12-O-tetra-decanoyl-phorbol-13-acetate (TPA) on the functions of guinea-pig smooth muscle taenia coli have been studied, using double-sucrose-gap method. A 15-20-min treatment of the muscle with 2 X 10(-8) M TPA caused a progressing inhibition of spontaneous electrical activity and mechanical tension, suppression of post-hyperpolarizing electrical and contractile "off-responses", a decrease in the number of action potentials during superthreshold membrane depolarization, depression of electrical and mechanical responses induced by acetylcholine, histamine, bradykinin mediators. The treatment of pre-depolarized (140 mM kappa+) muscle with 2.10(-8) TPA has led to a considerable reduction in contractile responses induced by the above mediators. The results obtained indicate that protein kinase C is capable of regulating both voltage-sensitive and receptor-operated ionic channels in smooth muscle cells.     

Identification of minor tightly bound H1 histone subfractions which fail to cleave their initiator methionine

Groups of CBA mice were administered [³⁵S] methionine (1 mCi/mouse). Non-histone proteins, H1 and H1⁰ histones and nucleosomal core histones were isolated from different issues by selective extractions. The measurements of radioactivity of individual bands and autoradiography of dry gels were used to identify methionine-containing and methionine-free histone variants. H1A and H1B histone variants extracted with 5% perchloric acid were methionine-free. However, minor sub-fractions of these histones which are more tightly bound to DNA (and which can be extracted only with 0.25 N HC1) contained [³⁵S] methionine and did show a higher specific activity than methionine-containing nucleosomal hitones. Cyanogen Bromide reaction which destroys non-histone proteins and methionine-containing nucleosomal histones removes radioactivity but does not alter the position of methionine-containing H1 minor bands. This indicates that the radioactive methionine occupies only the N-terminus of the H1 molecules. It is suggested that this methionine is an uncleaved initiator methionine. The presence of these methionine-containing minor H1 subfractions varies in different tissues.     

Spectral analysis and mathematical modeling of electrical cerebral activity in rats with genetically determined predisposition to seizure and in controls

Spectral signs of genetically determined predisposition to seizure characteristic of Krushinskii-Molodkina (KM) strain rats were found when studying summated cerebral potentials, namely increased power of low (1–3 Hz) frequencies in spectra of motor and visual cortex potentials together with an abrupt increase and a reduction respectively in the power of hippocampal and caudate nucleus potentials. Comparative spectra of summated electrical activity within neuronal networks [10] and those of experimentally obtained potentials as determined by modeled parameters simulating neuronal networks were found (an inverse problem of modeling). It was found that spectral signs of predisposition to seizure could reflect changes in the physiological properties of neuronal networks belonging to the rat brain structures investigated. It might be suggested on the basis of the calculations performed that genetic predisposition to seizure in KM strain rats is determined by attenuation of the inhibitory function of the caudate nucleus and by heightened excitability (reactivity) in neurons of the paleo- and neocortex.Institute of Higher Nervous Activity and Neurophysiology, Academy of Sciences of the USSR, Moscow. Translated from Neirofiziologiya, Vol. 22, No. 2, pp. 184–193, March–April, 1990.     

Comparative analysis of background activity of ventrolateral thalamic neurons in patients with parkinsonism and torsion muscle dystonia

In the course of neurosurgical interventions in 40 patients with parkinsonism and torsion muscle dystonia, the background activity (BA) was recorded from 124 neurons of the ventrolateral nucleus (VL) of the thalamus with the aid of microelectrodes during demarcation of boundaries between nuclear structures, and identification of zones within a nucleus. The following characteristic features of the BA in patients with parkinsonism were found: a relatively large proportion (71%) of cells with a burst pattern of activity; a great diversity of burst duration in the activity (short or prolonged bursts); a large proportion (67%) of cells with cyclic changes in the BA frequency; diverse patterns of cyclic modulation, where periods varied from fractions of a second (0.2–0.8 sec) to seconds (2–10 sec) or to tens of seconds (20–40 sec); cyclic successions of spike bursts with the rhythm typical of the peripheral tremor (3–7/sec) in a substantial proportion (40%) of the units.The background spike trains recorded in patients with torsion muscle dystonia consisted of separated spikes in the majority (69%) of units. Only short high-frequency discharges were found in the burst activity in this group; a cyclic BA pattern occurred much less frequently (in 23% of neurons); burst discharges at a 3–4/sec frequency were found only in 4% of the examined cells.The possible nature of motor disorders in patients with parkinsonism and torsion muscle dystonia and the mechanisms of the curing effects of cryodestruction of theVL of the thalamus in the treatment of the disease are discussed.Neirofiziologiya/Neurophysiology, Vol. 25, No. 4, pp. 246–253, July–August, 1993.     

Activation characteristics of ouabain-sensitive respiration and Na,K-ATPase in the kidney cortex and medullary zone of rats adapted to cold

The endogenous and ouabain-sensitive respiration and Na, K-ATPase activity in the cortex and kidneys medulla of the cold-acclimated male albino rats have been determined. The increase of the respiration rate has been stated to be caused by the Na-pump activation. The obtained changes of Na, K-ATPase activity are supposed to be connected with the regulation of concentration and sodium excretion function of kidneys.     

云南省角蝉科二新属二新种

最近我们从全国动物学科研单位和高等院校借调来大批的角蝉科标本,进行系统的分类研究,从中发现有二新属及二新种,均采自云南西双版纳,现在先把它们加以记载。     

Optical surface plasmon resonance biosensors in molecular fishing

An optical biosensor employing surface plasmon resonance (SPR; SPR-biosensor) is a highly efficient instrument applicable for direct real time registration of molecular interactions without additional use of any labels or coupled processes. As an independent approach it is especially effective in analysis of various ligand receptor interactions. SPR-biosensors are used for validation of studies on intermolecular interactions in complex biological systems (affinity profiling of various groups of proteins, etc.). Recently, potential application of the SPR-biosensor for molecular fishing (direct affinity binding of target molecules from complex biological mixtures on the optical biosensor surface followed by their elution for identification by LCMS/MS) has been demonstrated. Using SPR-biosensors in such studies it is possible to solve the following tasks: (a) SPR-based selection of immobilization conditions required for the most effective affinity separation of a particular biological sample; (b) SPR-based molecular fishing for subsequent protein identification by mass spectrometry; (c) SPR-based validation of the interaction of identified proteins with immobilized ligand. This review considers practical application of the SPR technology in the context of recent studies performed in the Institute of Biomedical Chemistry on molecular fishing of real biological objects.