Thrombin is an important agonist for platelet activation and plays a major role in hemostasis and thrombosis. Thrombin activates platelets mainly through protease-activated receptor 1 (PAR1), PAR4, and glycoprotein Ib. Because adenosine diphosphate and thromboxane A2 have been shown to cause platelet aggregation by concomitant signaling through Gq and Gi pathways, we investigated whether coacti...

Ornithine decarboxylase (ODC) and the polyamines play an essential role in brain cell replication and differentiation. We administered alpha-difluoromethylornithine (DFMO), an irreversible inhibitor of ODC, to neonatal rats on postnatal days 5-12, during the mitotic peak of the cerebellum, a treatment regimen that leads to selective growth inhibition and dysmorphology. In adulthood, cell signal...

The M1-muscarinic cholinergic receptor (M1AChR) stimulates the release of inositol phosphates (IPs) but does not activate adenylyl cyclase. The beta-adrenergic receptor (beta-AR) stimulates adenylyl cyclase but has no effect on IP release. Amino acid sequences corresponding to the second (I2) and third (I3) intracellular loops of the turkey erythrocyte beta-AR and a 12-amino acid segment near t...

PURPOSE The regulation of adenylyl cyclase by multiple signal systems was investigated by biochemical studies of the enzyme in ciliary processes and by in vivo intraocular pressure responses in the rabbit eye. METHODS Adenylyl cyclase enzyme activity was determined by radiometric assay using alpha-32 P-ATP as substrate. Drugs were administered to the rabbit eye by intravitreal injection or to...

The diversity of angiotensin II (Ang II) actions implies multiple receptor subtypes. To characterize these subtypes in rat mesangial cells, we used the angiotensin subtype 1A (AT1A) antagonist losartan (DuP 753), the subtype 2/1B (AT2/AT1B) antagonist PD 123319, and the AT2 antagonist CGP 42112A in radioreceptor and adenylyl cyclase assays. In radioligand binding competition experiments, approx...

Spatially restricting cAMP production to discrete subcellular locations permits selective regulation of specific functional responses. But exactly where and how cAMP signaling is confined is not fully understood. Different receptors and adenylyl cyclase isoforms responsible for cAMP production are not uniformly distributed between lipid raft and non-lipid raft domains of the plasma membrane. We...

In molluscan central neurons that express cAMP-gated Na+ current (INa,cAMP), estimates of the cAMP binding affinity of the channels have suggested that effective native intracellular cAMP concentrations should be much higher than characteristic of most cells. Using neurons of the marine opisthobranch snail Pleurobranchaea californica, we applied theory and conventional voltage clamp techniques ...

Consolidation of hippocampus-dependent memory is dependent on activation of the cAMP/Erk/MAPK (mitogen-activated protein kinase) signal transduction pathway in the hippocampus. Recently, we discovered that adenylyl cyclase and MAPK activities undergo a circadian oscillation in the hippocampus and that inhibition of this oscillation impairs contextual memory. This suggests the interesting possib...

In the present work we used various cell lines in order to study the possible effect of coxsackievirus B3 (CVB3) entry on the adenylyl cyclase transmembrane signalling system. A significant decrease (by about 10-20%) was found in forskolin-augmented as well as in A1F-4- and GTP gamma S-sensitive adenylyl cyclase activity in plasma membranes isolated from HeLa, HEp-2, Vero and green monkey kidne...

Vertebrate olfactory receptor neurons (ORNs) transduce odor stimuli into electrical signals by means of an adenylyl cyclase/cAMP second messenger cascade, but it remains widely debated whether this cAMP cascade mediates transduction for all odorants or only certain odor classes. To address this problem, we have analyzed the generator currents induced by odors that failed to produce cAMP in prev...