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Biomedical subjects

S Konishi

Publications and source records attributed to S Konishi.

At least 127 records · Page 7Linked to original sources
PubMed1985

Testing hypotheses about interclass correlations from familial data.

Testing problems concerning interclass correlations from familial data are considered in the case where the number of siblings varies among families. Under the assumption of multivariate normality, two test procedures are proposed for testing the hypothesis that an interclass correlation is equal to a specified value. To compare the properties of the tests, including a likelihood ratio test, Monte Carlo experiments are performed. Several test statistics are derived for testing whether two variables about a parent and child are uncorrelated. The proposed tests are compared with previous test procedures, using Monte Carlo simulation. A general procedure for finding confidence intervals for interclass correlations is also derived.

Analysis of Variance↗
PubMed1983

Inhibition of p-aminohippurate transport by cyclic GMP in rat kidney cortical slices.

The effect of cyclic GMP on the accumulation of p-aminohippurate (PAH) was investigated by using rat kidney cortical slices. When the slices were preincubated with cyclic GMP and thereafter incubated in the absence of the cyclic nucleotide for the assay of PAH transport, cyclic GMP inhibited PAH accumulation in the slices in a dose-dependent fashion. Pretreatment of the slices with dibutyryl cyclic GMP induced no inhibition of PAH uptake, but that with the combination of cyclic GMP and butyrate inhibited the accumulation to the same extent as did cyclic GMP. Guanosine and its monophosphate (GMP) had no effect on PAH accumulation in the slices. Inhibitory effect of cyclic GMP on PAH accumulation was not due to the changes of electrolyte content and water distribution in the slices. The slices pretreated with cyclic GMP at 0 degree C failed to decrease PAH accumulation. Cyclic GMP had no effect on organic cation (tetraethylammonium, TEA) transport in the slices. These evidence suggest that cyclic GMP may be able to modulate the rat renal transport system for PAH although this study does not explain the mechanism of inhibition of PAH transport by the cyclic nucleotide.

Aminohippuric Acids↗
PubMed1982

Role of substance P as a sensory transmitter in spinal cord and sympathetic ganglia.

The hypothesis that substance P (SP) might be a transmitter of primary sensory neurons was first proposed by Lembeck in 1953. A large amount of evidence supporting this hypothesis has recently accumulated, particularly since the elucidation of the chemical structure of SP by Leeman and her colleagues in 1971, which made a number of new approaches possible (e.g. radioimmunoassay for SP, immunohistochemistry and electrophysiological tests of SP action on central and peripheral neurons). SP is concentrated in certain primary afferent terminals in the spinal cord, is released therefrom when the dorsal roots are electrically stimulated, and exerts a powerful excitant action on spinal neurons. It is therefore likely that SP produces excitatory postsynaptic potentials (EPSPs) in spinal neurons, although the characteristics of SP-mediated EPSPs, i.e. their time course, ionic mechanisms, etc., remain to be revealed. Recent electrophysiological and neurochemical studies on the prevertebral ganglia of the guinea-pig strongly suggest that SP is released from axon collaterals of visceral primary afferent neurons in the ganglia and serves as a transmitter that generates non-cholinergic slow EPSPs in principal cells. There is evidence that this SP-mediated synaptic transmission in the sympathetic ganglia is under the influence of enkephalinergic presynaptic inhibition. Some preliminary experiments on the interaction between SP and enkephalins in the spinal cord are described.

Action Potentials↗
PubMed1982

Substance P as an excitatory transmitter of primary afferent neurons in guinea-pig sympathetic ganglia.

Electrophysiological and neurochemical experiments were carried out to examine a possible transmitter role substance P in the prevertebral ganglia of the guinea-pig. When potentials were recorded intracellularly from neurons of the isolated ganglia, stimulation of the pre- or postganglionic nerves elicited a non-cholinergic slow excitatory postsynaptic potential (EPSP). This synaptic potential was compared with the effects of substance P. Brief application of substance P caused a depolarization of the ganglion cells with a similar time course to that of the non-cholinergic slow EPSP. Changes in membrane resistance during the substance P-induced depolarization resembled those associated with the non-cholinergic slow EPSP. During the substance P-induced depolarization the non-cholinergic slow EPSP was markedly depressed. Attempts were made to determine the origin of the fibers eliciting the non-cholinergic slow EPSP. In the inferior mesenteric ganglia isolated together with preganglionic nerves that retained intact connections with spinal nerve roots, dorsal root stimulation evoked a non-cholinergic slow EPSP but not a cholinergic fast EPSP in the ganglion cells, whereas ventral root stimulation caused only cholinergic fast EPSPs. Following the prolonged treatment with capsaicin, the non-cholinergic slow EPSP was greatly depressed or abolished. Radioimmunoassay revealed that after ligation or section of pre- or postganglionic nerves an accumulation of substance P occurred in the proximal stumps of the interrupted nerves. Stimulation with high potassium medium evoked a release of immunoreactive substance P from the prevertebral ganglia and the release was calcium-dependent. The present findings suggests that axon collaterals of certain visceral primary efferents form synapses with principal cells in the prevertebral ganglia and release substance P as a transmitter for the non-cholinergic slow EPSP.

Adrenergic Fibers↗