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Biomedical subjects

R M Kobayashi

Publications and source records attributed to R M Kobayashi.

16 recordsLinked to original sources
PubMed1979

Monoamine neuron regulation of LRF neurons innervating the organum vasculosum laminae terminalis and median eminence.

The LRF content of the median eminence (ME) and organum vasculosum laminae terminalis (OVLT) was analyzed following lesions destroying the serotonin neurons of the midbrain raphe and the dopamine neurons of the zona incerta. Six weeks after zona incerta lesions the LFT content of both OVLT and ME was significantly reduced. Raphe lesions did not significantly reduce LRF content of the ME or OVLT. No changes in circulating LH content were noted after either lesion. These observations suggest that the dopamine neurons of the incerto-hypothalamic system may be involved in the regulation of LRF synthesis or release from LRF neurons innervating the ME and OVLT.

Animals↗
PubMed1978

Regional distribution of muscarinic cholinergic receptors in rat brain.

Using the tritiated ligand [3H]quinuclidinyl benzilate ([3H]QNB), a specific muscarinic cholinergic antagonist, the distribution of muscarinic receptors was determined in 75 specific brain regions and nuclei removed by microdissection as well as in large brain areas. [3H]QNB binding was highest in the caudate-putamen; other regions with high binding included the nucleus accumbens, cerebral cortex and hippocampus, certain limbic and thalamic nuclei, superior colliculus, pontine nuclei and the hypoglossal nucleus. Muscarinic cholinergic receptors may be concentrated in these regions. [3H]QNB binding generally correlated well with acetylcholinesterase staining in terminals and is consistent with certain sites as particularly enriched in cholinergic synapses.

Animals↗
PubMed1976

Brain stem auditory-evoked responses in suspected central pontine myelinolysis.

Central pontine myelinolysis was suspected in two chronic alcoholics who developed and recovered from a progressive spastic paresis of all muscles, that derived innervation at and below the level of the pons. In both cases, short-latency auditory-evoked responses aided in the diagnosis by indicating a slowing of conduction in the pontine auditory pathway, which varied in degree with the severity of the clinical manifestations of pontine demyelination.

Alcoholism↗
PubMed1976

Orofacial dyskinesia. Clinical features, mechanisms and drug therapy.

Orofacial or tardive dyskinesias are involuntary repetitive movements of the mouth and face. In most cases, they occur in older psychotic patients who are in institutions and in whom long-term treatment with antipsychotic drugs of the phenothiazine and butyrophenone groups is being carried out. These dyskinesias are frequent in occurrence and characteristically are irreversible. Several biochemical mechanisms have been proposed as causes, including hypersensitivity or partially deneverated brain dopamine receptors and low affinity of the offending drugs for brain muscarinic cholinergic receptors. Clinical therapy has been attempted primarily with drugs that antagonize dopamine receptors or deplete brain dopamine. The benefits of drug treatment have been variable and lack of consistent improvement has been discouraging. Early recognition of dyskinesia should be attempted, and the dose reduced or the drug omitted at the first sign.

Antipsychotic Agents↗
PubMed1975

Effects of stress on catecholamines and tyrosine hydroxylase activity of individual hypothalamic nuclei.

The effects of acute stress on norepinephrine (NE) and dopamine (DA) concentrations and of repeated stress on tyrosine hydroxylase (TH) activity were measured in individual hypothalamic nuclei and other rat brain regions. A microdissection technique and radioisotopic enzymatic assays enables these studies to be performed. NE and DA concentrations were reduced and TH activity increased selectively in the arcuate nucleus. These results suggest that the arcuate nucleus may be selectively involved in the stress response and support the hypothesis that catecholamines in the medial basal hypothalamus mediate certain of the neuroendocrine changes observed in stress.

Acute Disease↗
PubMed1975

Biochemical mapping of the noradrenergic projection from the locus coeruleus. A model for studies of brain neuronal pathways.

Mapping of the noradrenergic projection from neurons in the rat locus coeruleus has been examined by combining a sensitive radioisotopic assay for catecholamines with a microdissection technique to remove multiple separate brain nuclei. The effect of a unilateral locus coeruleus lesion on norepinephrine concentration in 19 brain regions ipsilateral and contralateral to the lesion was determined. Evidence for ipsilateral and bilateral innervation to specific regions is presented, and many regions appear to receive combined innervation from other noradrenergic loci, in addition to that from the locus coeruleus. Fluorescence rating was correlated with biochemical measurement of amine content with these techniques and proportionality was observed over a narrow range. With this proportionality taken into consideration, mapping results obtained by biochemical and fluorescence methods are compared.

Animals↗