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L Koda

Publications and source records attributed to L Koda.

7 recordsLinked to original sources
PubMed1988

Penetration of fluorescein into the brain: a sex difference.

Fluorescein was found to penetrate into the brain via the circumventricular organs. Fluorescein penetrates beyond the borders of the circumventricular organs into the surrounding neuropile. This relationship was found for the area postrema and the nucleus tractus solitarius, the organum vasculosum lamina terminalis and the rostral suprachiasmatic area, the median eminence and the arcuate nucleus. The choroid plexus appears to take up fluorescein, but fluorescence does not appear in adjacent structures such as the corpus striatum and septum, but rather along the ependymal and plial surfaces. Fluorescein was found to accumulate to a greater extent in the brains of female as compared to male rats. This sex difference is not associated with the blood-brain barrier as cortex and cerebellum did not show increased fluorescence, but only midline structures containing circumventricular organs. Gonadectomy did not alter fluorescein accumulation.

Animals↗
PubMed1984

Evidence for selective release of somatostatin-14 and somatostatin-28(1-12) from rat hypothalamus.

Cysteamine administration to rats results in a marked depletion of hypothalamic somatostatin-14 (SS14) and a decrease of the potassium-evoked in vitro release of SS14 without a significant change in the content or release of somatostatin-28(1-12)-like immunoreactivity (SS28(1-12)-L1). Furthermore, cysteamine enhances the spontaneous release and markedly potentiates the potassium-evoked release of SS14 in the in vitro slice preparation. However, in vitro-administered cysteamine does not alter the spontaneous or potassium-evoked release of SS28(1-12)-LI. Immunohistochemical visualization of hypothalamic neuronal cell bodies and fibers following cysteamine administration shows a disappearance of the SS14 immunoreactive fibers and cell bodies with no apparent change in the SS28(1-12) immunoreactive fibers and cell bodies. These data suggest that, in rat hypothalamus, selective release of SS14 and SS28(1-12) can occur. The results are discussed in relation to possible sites of storage and release of the somatostatin-related peptides from synaptic nerve terminals.

Animals↗
PubMed1983

Chemical and physiological aspects of the actions of lithium and antidepressant drugs.

The possible mechanisms underlying the anti-manic actions of lithium have been examined in a variety of interdisciplinary experiments. The possibility that lithium can regulate the sensitivity changes in dopaminergic transmission produced by chronic treatment with haloperidol has been tested. Although a modest modification of behavioral responses to the dopamine agonist apomorphine was found, there was no evidence that this action of lithium reflected alterations of the binding parameters of dopamine-related ligands. In other studies, consistent, dose-dependent increases in brain enkephalin content were found after rats consumed a specially manufactured lithium diet for 2-3 weeks. Not only were brain enkephalin levels increased after this treatment, but some signs of basal analgesic responsiveness also suggested that the elevated levels of enkephalins were functionally significant. To test the possibility that the effects of lithium may not be seen in normal rats, the effects of lithium were compared on spontaneously hypertensive and unaffected, normotensive rats of a related strain. Treatment with lithium altered blood pressure in the hypertensive strain but did not affect blood pressure in the controls. These studies suggest that multiple brain systems may be regulated by treatment with lithium but that the critical pathophysiological process may not be demonstrable in the normal rat.

Animals↗
PubMed1980

Regional distribution of endorphin, Met5-enkephalin and Leu5-enkephalin in the pigeon brain.

The distribution of beta-endorphin and enkephalin in the pigeon forebrain by immunohistochemistry and radioimmunoassay is essentially analogous to mammals. Both endorphin- and enkephalin-reactive fibers have a similar periventricular distribution, but the enkephalin fibers are more extensive and are also found in the paleostriatum, limbic regions and brain stem, pituitary stalk and notably, penetrating the organum vasculosum hypothalami. There was poor correlation between endorphin and enkephalin regional contents by radioimmunoassay. In contrast, a highly significant correlation was observed between Met5-enkephalin and Leu5-enkephalin regional distribution. These data support the view that enkephalin neurons and endorphin neurons are independent central neuronal systems.

Animals↗