Biomedical subjects

A Vogl

Publications and source records attributed to A Vogl.

At least 19 recordsLinked to original sources

PubMed2000

Cross-talk between olfactory second messenger pathways.

The second messengers 3'-5'-cyclic-monophosphate (cAMP) and inositol 1,4,5-trisphosphate (InsP3) have been implicated in olfactory signal transduction in various species. The results of the present study provide evidence that the two olfactory second messenger pathways in rat olfactory neurons do not work independently but rather show a functional antagonism: whereas inhibition of phospholipase C (PLC) in isolated olfactory cilia by U-73122 led to an augmentation of odor-induced cAMP signaling, activation of the phosphoinositol pathway resulted in attenuation of odor-induced cAMP formation. Furthermore, this study indicates that elevated cAMP levels cause suppression of odor-induced InsP3 signaling, whereas inhibition of adenylate cyclase (AC) by cisN-(2-phenylcyclopentyl)azacylotridec-1-en-2-amine (MDL-12,330 A) results in potentiation of odor-induced InsP3 formation. Concerning the molecular mechanism involved in cross-interaction, the experimental data indicate that the observed antagonism of elevated cAMP is based on inhibition of PLC activation rather than on stimulation of InsP3 degradation. As blockage of the endogenous protein kinase A (PKA) prevented the inhibitory effect of cAMP, the suppression of odor-induced InsP3 signaling by cAMP may be mediated by a PKA-controlled reaction.

Adenylyl Cyclase Inhibitors↗

PubMed1999

Identification of a cyclic nucleotide- and voltage-activated ion channel from insect antennae.

From an antennal cDNA library of Heliothis virescens a clone has been isolated encoding a polypeptide of 678 amino acids. Data base comparisons and primary structure analysis of the deduced protein sequence (HvCNG) indicated significant homology to cyclic nucleotide and voltage-activated ion channels including six putative membrane spanning domains, a putative cyclic nucleotide binding site, a pore region and a voltage-sensor motif. Heterologous expression of the cloned cDNA in Sf9 cells resulted in a polypeptide of the predicted molecular mass. Patch clamp analysis allowed to record the activity of the identified HvCNG channels; they were activated by cAMP but also by hyperpolarization. The channel displayed in potassium solution a conductance of 30 pS; the ion selectivity was calculated as PK/PNa approximately 3. Northern blot analysis revealed that the channel is highly expressed in the antennae; weaker signal were detected in heads and legs. In situ hybridization of tissue sections through the antennae showed a spatial distribution of reactive cells; they are located beneath sensillar hairs. Thus, a novel channel type has been identified which may play an important role in antennal cells.

Amino Acid Sequence↗

PubMed1994

IMMUNOLOCALIZATION OF H+-ATPase IN THE GILL EPITHELIA OF RAINBOW TROUT

The localization of proton pumps (H+-ATPase) in gill epithelia of rainbow trout [Oncorhynchus mykiss (Walbaum)] was elucidated by immunofluorescence microscopy, using rabbit polyclonal antibodies against the 70 kDa subunit of H+-ATPase purified from clathrin-coated vesicles of bovine brain. In the gill epithelia of freshwater trout, the immunostaining was uniformly distributed along the lamellae and generally concentrated in apical regions. It is concluded, therefore, that H+-ATPase is located in the apex of both chloride cells and epithelial cells of freshwater fish. Hypercapnic treatment resulted in a non-polarized and restrictive distribution of H+-ATPase in the chloride cell. No fluorescent staining was observed in the gill epithelium of seawater-adapted rainbow trout, except in some unidentified anucleate surface material. The presence of the 70 kDa subunit in fish gill epithelia was confirmed by Western blot. These results support the proposed role of a proton pump in sodium uptake in freshwater fish and demonstrate that the H+-ATPase in fish gills is of the vacuolar type, antigenically similar to the H+-ATPase in mammalian brain and kidney.

Journal Article↗

PubMed1984