Cholecystokinin was administered systemically while recordings were taken of the evoked action potential in the hippocampal dentate gyrus to stimulation of the medial entorhinal cortex. The sulphated octapeptide and t. BOC CCK-4, but not the unsulphated octapeptide or tetrapeptide, increased the amplitude of the evoked action potential in a dose-dependent manner, whereas the unsulphated octapeptide decreased it. Bilateral vagotomy did not block the effect of the sulphated octapeptide. CR 1409 was also found to increase the amplitude of the evoked response and did not block the effect of subsequent administration of sulphated octapeptide. These results are consistent with action at a central receptor locus.

Action Potentials↗

PubMedDate not supplied

Central administration of cholecystokinin potentiates evoked potential amplitude in the hippocampal dentate gyrus.

Cholecystokinin and related ligands were injected into a lateral ventricle and recordings made of the field potential in the hippocampal dentate gyrus evoked by stimulation of the medial entorhinal cortex. With the exception of the unsulfated octapeptide, these compounds induced an increase in population action potential amplitude. The unsulfated octapeptide was found to inhibit the action of its sulfated congener, and alone induced a decrease in response amplitude. These results suggest a modulation of intracortical activation of the dentate gyrus by cholecystokinin, and that this action is probably mediated by a central-type receptor.

Animals↗

PubMedDate not supplied

Relationship between serum adiponectin concentration and intramyocellular lipid stores in humans.

The recently identified adipocytokine adiponectin has been shown to improve insulin action and decrease triglyceride content in skeletal muscle (by stimulating lipid oxidation) in mice. In the present study, we tested the hypothesis that high serum concentrations of adiponectin are associated with lower intramyocellular (IMCL) fat content by promoting lipid oxidation in humans. IMCL-content in predominantly non-oxidative tibialis anterior muscle and oxidative soleus was determined by proton magnetic resonance spectroscopy in a cross- sectional study involving 63 healthy volunteers. In a second set of experiments, changes in IMCL in both muscles were measured after a three days dietary lipid challenge (n = 18) and after intravenous lipid challenge (n = 12) with suppressed lipid oxidation under hyperinsulinemia. Adiponectin serum concentrations were found to be negatively correlated with IMCL in the oxidative soleus muscle (IMCL [sol]) (r = - 0.46, p < 0.001) independent of measures of obesity, but not with IMCL in the non-oxidative tibialis anterior muscle (IMCL [tib]) (p = 0.40). Adiponectin serum concentrations were negatively correlated with the observed increase in IMCL load after dietary lipid challenge in the tibialis (r = 0.53, p = 0.03) but not in the soleus muscle. During suppression of lipid oxidation by hyperinsulinemia, no effect of adiponectin on IMCL was observed in either soleus or tibialis muscle. Overall, the presented findings are consistent with the hypothesis that adiponectin promotes lipid oxidation in humans resulting in lower intracellular lipid content in human muscle. These results are consistent with animal data, where adiponectin could be shown to enhance lipid oxidation and reduce muscle triglycerides.

Adiponectin↗

PubMedDate not supplied

Neuroendocrine carcinoma of the skin (Merkel cell carcinoma): ultrastructural and immunohistochemical demonstration of neurofilaments.

In this study we characterized a skin tumor that grew in the temporal region of a 69-year-old woman. On the basis of tumor morphology, a metastasis from a small cell carcinoma of the lung was initially suggested, but X-ray and bronchoscopic studies were negative. The tumor recurred twice within a year, yet no tumors were found elsewhere in the body. Ultrastructurally, cytoplasmic organelles compatible with neuroendocrine storage granules and perinuclear aggregates of intermediate-sized (8-10 nm) filaments were found in many tumor cells. Indirect immunofluorescence microscopy revealed neurofilament-type intermediate filaments in the tumor cells but no keratin- or vimentin-type filaments. Our results further demonstrate neural properties of this tumor type, which is generally considered to have its origin from Merkel cells, the cutaneous neuroendocrine cells.

Aged↗

PubMedDate not supplied

[Sound impulses occurring during drilling processes and their harmful effect on the hearing organs].

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Hearing Disorders↗