Search results for "Pineal gland"
showing 3 items of 143 documents
Das Werk der inneren Uhr Zur Neuroanatomie des circadiauen Systems der S�uger
1993
Many aspects of mammalian life exhibit distinct alterations throughout the 24-h cycle. Morphological, physiological, and biochemical parameters display circadian rhythms which are thought to be generated by an endogenous pacemaker and regulated by environmental factors. The morphological substrates of the endogenous circadian system have been studied extensively during the last two decades. Although knowledge is far from complete, there is general agreement that the pathways involved consist mainly of retina, hypothalamus, spinal cord, sympathetic trunk, and pineal gland. This review characterizes the anatomical structures and tracts responsible for generation and maintenance of circadian r…
Clorgyline effect on pineal melatonin biosynthesis in adrenalectomized rats pretreated with 6-hydroxydopamine
1994
The response to administration of the specific monoamine oxidase A (MAO-A) blocker clorgyline was investigated in adult male Sprague-Dawley rats which were adrenalectomized four days prior to treatment or were additionally sympathectomized as newborns by injection of 6-hydroxydopamine. In both groups, the contents of pineal indoles melatonin and N-acetylserotonin were augmented, and the contents of 5-hydroxyindoleacetic acid and 5-hydroxyindoletryptophol decreased 90 min following clorgyline injections when compared to rats receiving saline. The observed responses were less pronounced in rats both adrenalectomized and sympathectomized. The results are in line with the hypothesis that preser…
Vasoactive intestinal peptide stimulation of cyclic guanosine monophosphate formation: further evidence for a role of nitric oxide synthase and cytos…
1993
In the rat pineal gland vasoactive intestinal peptide (VIP) and beta-adrenergic agonists stimulate cyclic guanosine monophosphate (cGMP) formation and their action is amplified by alpha 1-adrenergic agonists. Since beta-adrenergic stimulation of cGMP is suggested to involve activation of nitric oxide (NO) synthase and NO-mediated activation of cytosolic guanylate cyclase (GC), we investigated the effects of the NO synthase inhibitor N-monomethyl-L-arginine (L-NMMA) and of the cytosolic GC inhibitor methylene blue (MB) on VIP receptor-stimulated cGMP formation. Both L-NMMA and MB depressed VIP-induced cGMP formation as well as alpha 1-adrenergic potentiation of VIP-stimulated cGMP formation …