TY  - GEN
A1  - Rein, Julia
A1  - Voss, Martin
A1  - Blenau, Wolfgang
A1  - Walz, Bernd
A1  - Baumann, Otto
T1  - Hormone-induced assembly and activation of V-ATPase in blowfly salivary glands is mediated by protein kinase A
N2  - The vacuolar H+-ATPase (V-ATPase) in the apical membrane of blowfly (Calliphora vicina) salivary gland cells energizes the secretion of a KCl-rich saliva in response to the neurohormone serotonin (5-HT). We have shown previously that exposure to 5-HT induces a cAMP-mediated reversible assembly of V-0 and V-1 subcomplexes to V-ATPase holoenzymes and increases V-ATPase-driven proton transport. Here, we analyze whether the effect of cAMP on V-ATPase is mediated by protein kinase A (PKA) or exchange protein directly activated by cAMP (Epac), the cAMP target proteins that are present within the salivary glands. Immunofluorescence microscopy shows that PKA activators, but not Epac activators, induce the translocation of V1 components from the cytoplasm to the apical membrane, indicative of an assembly of V-ATPase holoenzymes. Measurements of transepithelial voltage changes and microfluorometric pH measurements at the luminal surface of cells in isolated glands demonstrate further that PKA-activating cAMP analogs increase cation transport to the gland lumen and induce a V-ATPase-dependent luminal acidification, whereas activators of Epac do not. Inhibitors of PKA block the 5-HT-induced V-1 translocation to the apical membrane and the increase in proton transport. We conclude that cAMP exerts its effects on V-ATPase via PKA.
KW  - Vacuolar h+-atpase
KW  - camp binding-sites
KW  - cyclic-amp
KW  - plasma-membrane
KW  - drosophila-melanogaster
Y1  - 2008
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-46126
ER  - 
TY  - GEN
A1  - Blenau, Wolfgang
A1  - Rotte, Cathleen
A1  - Witte, Jeannine
A1  - Baumann, Otto
A1  - Walz, Bernd
T1  - Source, topography and excitatory effects of GABAergic innervation in cockroach salivary glands
N2  - Cockroach salivary glands are innervated by dopaminergic and serotonergic neurons. Both transmitters elicit saliva secretion. We studied the distribution pattern of neurons containing gamma-aminobutyric acid ( GABA) and their physiological role. Immunofluorescence revealed a GABA-immunoreactive axon that originates within the subesophageal ganglion at the salivary neuron 2 (SN2) and this extends within the salivary duct nerve towards the salivary gland. GABA-positive fibers form a network on most acinar lobules and a dense plexus in the interior of a minor fraction of acinar lobules. Co-staining with anti-synapsin revealed that some putative GABAergic terminals seem to make pre-synaptic contacts with GABA-negative release sites. Many putative GABAergic release sites are at some distance from other synapses and at distance from the acinar tissue. Intracellular recordings from isolated salivary glands have revealed that GABA does not affect the basolateral membrane potential of the acinar cells directly. When applied during salivary duct nerve stimulation, GABA enhances the electrical response of the acinar cells and increases the rates of fluid and protein secretion. The effect on electrical cell responses is mimicked by the GABA(B) receptor agonists baclofen and SKF97541, and blocked by the GABAB receptor antagonists CGP52432 and CGP54626. These findings indicate that GABA has a modulatory role in the control of salivation, acting presynaptically on serotonergic and/or dopaminergic neurotransmission.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - paper 111 
KW  - GABA
KW  - salivary gland
KW  - innervation
KW  - cockroach
KW  - Periplaneta americana
Y1  - 2009
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-44353
ER  - 
TY  - GEN
A1  - Schmälzlin, Elmar
A1  - Walz, Bernd
A1  - Klimant, Ingo
A1  - Schewe, Bettina
A1  - Löhmannsröben, Hans-Gerd
T1  - Monitoring hormone-induced oxygen consumption in the salivary glands of the blowfly, Calliphora vicina, by use of luminescent microbeads
N2  - The salivary glands of the blowfly were injected with luminescent oxygen-sensitive microbeads. The changes in oxygen content within individual gland tubules during hormone-induced secretory activity were quantified. The measurements are based on an upgraded phase-modulation technique, where the phase shift of the sensor phosphorescence is determined independently from concentration and background signals. We show that the combination of a lock-in amplifier with a fluorescence microscope results in a convenient setup to measure oxygen concentrations within living animal tissues at the cellular level.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - paper 006 
Y1  - 2006
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-12206
ER  -