Browsing by Author "Jennes, Lothar"

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Distribution of ionotropic glutamate receptor subunit mRNAs in the rat hypothalamus
(Wiley-Liss, 2001-05-21) Centers, Adrian; Jennes, Lothar; Özhan, Eyigör; Uludağ Üniversitesi/Tıp Fakültesi/Histoloji ve Embriyoloji Anabilim Dalı.; 0000-0003-3463-7483
The excitatory amino acid neurotransmitter glutamate participates in the control of most (and possibly all) neuroendocrine systems in the hypothalamus. This control is exerted by binding to two classes of membrane receptors, the ionotropic and metabotropic receptor families, which differ in their structure and mechanisms of signal transduction. To gain a better understanding about the precise sites of action of glutamate and the subunit compositions of the receptors involved in the glutamatergic neurotransmission in the hypothalamus and septum, in situ hybridization was used with S-35-labeled cRNA probes for the different ionotropic receptor subunits, including glutamate receptor subunits 1-4 (GluR1-GluR4), kainate-2, GluR5-GluR7, N-methyl-D-aspartate (NMDA) receptor 1 (NMDAR1), and NMDAR2A-NMDAR2D. The results showed that subunits of alpha -amino-3-hydroxy-5-methyl-4-isoxazole-propionate-preferring, kainate-preferring, and NMDA-preferring receptor subunits are distributed widely but heterogeneously and that the GluR1, GluR2, kainate-2, NMDAR1, NMDAR2A, and NMDAR2B subunits are the most abundant in the hypothalamus. Thus, GluR1 subunit mRNA was prominent in the lateral septum, preoptic area, mediobasal hypothalamus, and tuberomammillary nucleus, whereas kainate-2 subunit mRNA was abundant in the medial septum-diagonal band, median and anteroventral preoptic nuclei, and supraoptic nuclei as well as the magnocellular portion of the posterior paraventricular nucleus. Regions that contained the highest levels of NMDAR1 subunit mRNA included the septum, the median preoptic nucleus, the anteroventral periventricular nucleus, and the supraoptic and suprachiasmatic nuclei as well as the arcuate nucleus. Together, the extensive distribution of the different GluR subunit mRNAs strengthen the view that glutamate is a major excitatory neurotransmitter in the hypothalamus. The overlap in the distribution of the various subunit mRNAs suggests that many neurons can express GluR channels that belong to different families, which would allow a differential regulation of the target neurons by glutamate.
Identification of kainate-preferring glutamate receptor subunit G1uR7 mRNA and protein in the rat median eminence
(Elsevier, 1998-12-14) Jennes, Lothar; Eyigör, Özhan; Uludağ Üniversitesi/Tıp Fakültesi/Histoloji ve Embriyoloji Anabilim Dalı.; 0000-0003-3463-7483; ABE-5128-2020
In situ hybridization and immunohistochemistry were used to determine the presence of kainate-preferring glutamate receptor subunits GluR6 and GluR7 mRNA and protein in the median eminence of the rat. The results show that most tanycytes lining the ventral third ventricle and many astrocytes within the median eminence contain the GluR7 receptor subunit mRNA but not the GluR5 and GluR6 receptor subunit mRNA. Immunohistochemical stainings show that the GluR6/7 receptor protein was localized to tanycytic cell bodies, their basal processes and to many other astrocytes in different layers of the median eminence. The results suggest that glutamate can act directly on the glial cells in the median eminence by binding to the GluR7 subunit which may be important for the control of the secretion of releasing and inhibiting hormones from axon terminals in the external layer. In order to determine if these receptor subunits are functional, kainic acid was injected and c-fos expression monitored. Results show that kainic acid induced c-Sos synthesis in most of these glial cells.
Microwave-assisted antigen retrieval and incubation with cox-2 antibody of archival paraffin-embedded human oligodendroglioma and astrocytomas
(Elsevier, 2006-09-30) Jennes, Lothar; Temel, Sehime G.; Minbay, F. Zehra; Kahveci, Zeynep; Uludağ Üniversitesi/Tıp Fakültesi/Histoloji ve Embriyoloji Anabilim Dalı.; Uludağ Üniversitesi/Tıp Fakültesi/Tıbbi Genetik Anabilim Dalı.; 0000-0001-5757-8450; AAG-8385-2021; ABC-1475-2020; 6507885442; 8220935200; 6603395784
Immunohistochemistry is an important toot that is often used for the diagnosis of pathologies; however, the length of time required to process the tissue is relatively long. Furthermore, the quality and sensitivity of immunohistochemical staining is affected by formalin fixation which results in variable loss of antigenicity, known as masking effect. Here we assess the effect of microwave irradiation on the incubation time required to obtain high quality immunohistochemical staining for cox-2 using archival formalin-fixed, paraffin-embedded human oligodendrogliomas and astrocytomas. The results show that intermittent microwave irradiation during the incubation with the primary antibody reduced the time requirement to 5 min while the staining quality was indistinguishable from 1 or 24 h long incubations. Thus, the use of this procedure results in a significant saving of time which is important for a timely diagnosis of pathological conditions that await treatment.