Hermann Ammer

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Western-blot analysis of human neuroblastoma SH-SY5Y cells (mu- and delta-receptors) revealed the presence of the following G-protein subunits: Gi alpha 1, Gi alpha 2, Gs alpha, G(o) alpha, Gz alpha, and G beta, a pattern resembling that observed in central nervous tissue. Chronic treatment of differentiated [all-trans-retinoic acid (10 microM; 6 days)](More)
Western blot analysis, using subtype-specific anti-G protein antibodies, revealed the presence of the following G protein subunits in human neuroblastoma SH-SY5Y cells: Gs alpha, Gi alpha 1, Gi alpha 2, Go alpha, Gz alpha, and G beta. Differentiation of the cells by all-trans-retinoic acid (RA) treatment (10 mumol/L; 6 days) caused substantial alterations(More)
G proteins have been implicated in the development of opioid dependence of the guinea pig myenteric plexus as chronic fentanyl elevates G0/i alpha and pertussis toxin prevents this phenomenon. Therefore, the present study investigates G proteins more closely in this peripheral nerve plexus after chronic exposure to addictive drugs of the opiate and(More)
Chronic exposure of all-trans-retinoic acid-differentiated SH-SY5Y cells to morphine (10 mu M; 2 days) results in sensitization of adenylate cyclase as characterized by a significant increase in both PGE1 receptor-mediated as well as receptor-independent (NaF, 10 mM; forskolin, 100 mu M) stimulation of effector activity. To investigate the underlying(More)
Prolonged exposure of neuroblastoma x glioma (NG 108-15) hybrid cells to inhibitory acting drugs results in sensitization of adenylate cyclase. We now report that chronic activation (3 days) of either inhibitory delta-opioid receptors, alpha 2B-adrenoceptors, or muscarinic M4 receptors significantly decreases the number of stimulatory, adenylate(More)
Chronic opioid treatment of stably mu-opioid receptor transfected human mammary epidermoid A431 carcinoma cells (clone A431/mu 13) results in sensitization of adenylyl cyclase (AC), a cellular adaptation associated with drug dependence. Up-regulation of AC is characterized by significantly increased levels of both basal and post-receptor-stimulated effector(More)
Chronic opioid regulation of stimulatory beta-2 adrenoceptor (beta-2 AR) signaling was investigated in human mammary epidermoid carcinoma A431 cells stably expressing the cloned rat mu opioid receptor. In the cell clone used (A431/mu 13; Bmax = 302.9 +/- 46 fmol/mg membrane protein), the addition of morphine acutely attenuated basal as well as(More)
Inflammatory pain is counteracted by a number of physiological processes. For example, opioid receptors, which are present on peripheral terminals of sensory neurons, are activated by endogenous opioids, which are released from immune cells migrating to the inflamed tissue. Earlier data demonstrated that interleukin-6 contributes to such(More)
The tumor suppressor Fhit protein is defective or absent in many tumor cells due to methylation, mutation or deletion of the FHIT gene. Despite numerous attempts to unravel the functions of Fhit, the mechanisms by which the function and expression of Fhit are regulated remain poorly understood. We have recently shown that activated Gαq subunits interact(More)
delta-Opioid receptor (DOR) agonists possess cytoprotective properties, an effect associated with activation of the "pro-survival" kinase Akt. Here we delineate the signal transduction pathway by which opioids induce Akt activation in neuroblastomaxglioma (NG108-15) hybrid cells. Exposure of the cells to both [D-Pen(2,5)]enkephalin and etorphine resulted in(More)