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1.
ATP-induced membrane durrents in the submucous neurons of the guinea pig small intestine were studied using the whole-cell patch-clamp recording technique. Being applied at –50 mV. ATP activated an inward non-selective cationic current in 68.3% of the investigated neurons. An increase in ATP concentration within the 1–1,000 µM range resulted in the s-like increase in the amplitude of ATP-induced current. The EC50 was 150.0±18.5 µM, while the Hill number was 1.6. The current was selectively activated by ATP and was not blocked by P2 purinoreceptor antagonist suramin (50–300 µM).,-Methylene-ATP (100–200 µM) and,-methylene-ATP (100–200µM), which are P2-purinoreceptor agonists, as well as adenosine (100–300 µM), exerted no effects. Reactive blue 2, if applied up to 4 min, enhanced ATP-induced current, while its longer application partially suppressed this current. In most submucous neurons, acetylcholine (ACh) likewise activated an inward cationic current. The amplitude of ACh-induced current was lower if ACh was applied during a long-lasting application of ATP than if ACh only was applied. Hexamethonium (50 µM), d-tubocurarine (20–40 µM), and trimethaphan (30 µM) completely and reversibly blocked ACh-induced currents, regardless of the presence of ATP, and did not affect ATP-induced currents. The results suggest that ATP-induced currents in submucous neurons are due to activation of a unique type of P2 purinoreceptors, which function in connection with nicotinic ACh receptors.Neirofiziologiya/Neurophysiology, Vol. 28, No. 2/3, pp. 100–110, March–June, 1996. 相似文献
2.
mtDNA diversity in rhesus monkeys reveals overestimates of divergence time and paraphyly with neighboring species 总被引:4,自引:0,他引:4
Reconstructions of the human-African great ape phylogeny by using
mitochondrial DNA (mtDNA) have been subject to considerable debate. One
confounding factor may be the lack of data on intraspecific variation. To
test this hypothesis, we examined the effect of intraspecific mtDNA
diversity on the phylogenetic reconstruction of another Plio- Pleistocene
radiation of higher primates, the fascicularis group of macaque (Macaca)
monkey species. Fifteen endonucleases were used to identify 10 haplotypes
of 40-47 restriction sites in M. mulatta, which were compared with similar
data for the other members of this species group. Interpopulational,
intraspecific mtDNA diversity was large (0.5%- 4.5%), and estimates of
divergence time and branching order incorporating this variation were
substantially different from those based on single representatives of each
species. We conclude that intraspecific mtDNA diversity is substantial in
at least some primate species. Consequently, without prior information on
the extent of genetic diversity within a particular species, intraspecific
variation must be assessed and accounted for when reconstructing primate
phylogenies. Further, we question the reliability of hominoid mtDNA
phylogenies, based as they are on one or a few representatives of each
species, in an already depauperate superfamily of primates.
相似文献
3.
Conducting pathways of ganglia from the lumbar portion (L3–L5) of the sympathetic trunk in rabbits were studied by recording action potentials from nerves of the ganglia evoked by stimulation of other nerves of these ganglia, and by intracellular recording from single neurons. Besides the well-known system of descending preganglionic fibers, which enter the trunk through white rami communicantes and, as they pass through the ganglia, form synapses on ganglionic neurons, some preganglionic fibers were shown to enter the sympathetic chain through gray rami communicantes and to run in both ascending and descending directions, forming synaptic connections with neurons of the lumbar ganglia.A. A. Bogomolets Institute of Physiology, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Neirofiziologiya, Vol. 16, No. 2, pp. 247–254, March–April, 1984. 相似文献
4.
Two types of slow excitatory postsynaptic potentials (EPSPs) with different properties were found in neurons of the rabbit superior cervical sympathetic ganglion. In our group of neurons slow EPSPs increased during artificial hyperpolarization and decreased during depolarization of the membrane. The input resistance of the cells fell or remained unchanged during the development of slow EPSPs. In the second group of cells slow EPSPs increased during depolarization and decreased during hyperpolarization. The reversal potential of these responses, determined by extrapolation, was –78.9±3.6 mV. Depolarization responses to activation of muscarinic cholinergic receptors by acetylcholine or carbachol developed in 53% of neurons with an increase in input resistance and had a reversal potential of –83.2±6.7 mV. It is suggested that in cells of the first group the ionic mechanism of the slow EPSPs is similar to that of the fast EPSPs, whereas in cells of the second group its main component is a decrease in the potassium conductance of the membrane.A. A. Bogomolets Institute of Physiology, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Neirofiziologiya, Vol. 13, No. 4, pp. 371–379, July–August, 1981. 相似文献
5.
Natural electrical activity in the left greater splanchnic nerve during feeding was studied in chronic experiments on dogs. The method of separation of coherent components in pulsed form was used to analyze the discharges: Recording from the nerve was carried out at two points; activity was delayed by the time for its conduction along the nerve between the channels, in the channel which received it first, and it was then led from both channels to the coincidence unit. Spontaneous afferent impulsation was shown to spread among a group of nerve fibers with conduction velocities of between 3.7 and 20 m/sec, and with a mean velocity for the maximum of activity of 9.2±1.0 m/sec. Efferent spontaneous activity was not detected. During feeding with meat, besides spontaneous activity, activity of a group of afferent fibers with conduction velocities within the range 3.7–9.2 m/sec also was found (the mean velocity for the maximum of activity was 5.8±0.7 m/sec), and also activity of a group of efferent fibers with conduction velocities within the range 2.5–9.8 m/sec (mean value for maximum 3.5±0.5 m/sec).A. A. Bogomolets Institute of Physiology, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Neirofiziologiya, Vol. 13, No. 6, pp. 636–642, November–December, 1981. 相似文献
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8.
Julie Chaumeil Mariann Micsinai Panagiotis Ntziachristos Ludovic Deriano Joy M.-H. Wang Yanhong Ji Elphege P. Nora Matthew J. Rodesch Jeffrey A. Jeddeloh Iannis Aifantis Yuval Kluger David G. Schatz Jane A. Skok 《Cell reports》2013,3(2):359-370
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9.
The background activity of pacemaker-like neurons (PLN) of the guinea-pig caudal mesenteric ganglion (CMG) and their reflex responses to colonic distention were studied on combined isolated preparations including the CMG and a colon segment connected with the lumbar colonic nerves. The results allow us to suggest that the spontaneous and reflex activity of PLN is of a peripheral origin. Synaptic transmission in the peripheral colonofugal nerve pathways is mediated by acetylcholine and substance P (SP). The SP-induced excitation of PLN probably involves activation of the tachykinin NK3 receptors. 相似文献
10.
Skok MV Lykhmus OY Bobrovnik SO Solodova OV Tzartos SJ Tsouloufis T Vanderesse R Marraud M 《Ukrainski? biokhimicheski? zhurnal》2002,74(4):54-60
The antibodies to nicotinic acetylcholine receptor alpha(181-192) synthetic peptides were elicited in rabbits and mice using the peptides conjugated to protein carriers in different orientations, either through C-terminal Cys (S-conjugates), or through amino groups (N-conjugates). S-conjugated peptides were less potent in eliciting peptide-specific antibodies compared to N-conjugates and this type of conjugation resulted in antibodies to the coupling reagent. However, the epitopes present in either S- or N-conjugated peptides appeared to be similar, indicating that amino acid residues, which form the epitope, were located in the middle part of the peptide and did not include both N- and C-terminal residues. Peptide conjugation to a protein carrier did not play a role in stabilizing the peptide conformation, but was necessary to concentrate the peptide epitopes on the carrier surface enabling bivalent antibody binding. 相似文献