Adenosine A1 receptors induce an inhibition of adenylyl cyclase via G-proteins of the Gi/o family. In addition, simultaneous stimulation of A1 receptors and of receptor-mediated activation of phospholipase C (PLC) results in a synergistic potentiation of PLC activity. Evidence has accumulated that Gbetagamma subunits mediate this potentiating effect. However, an A1 receptor-mediated increase in...

The influence of adenosine receptor ligands on ketamine-induced locomotor activity was studied in mice. Ketamine-induced hyperactivity (10 mg/kg) was significantly and dose-dependently attenuated by CGS 21680 (selective A(2A) receptor agonist), and NECA (A1/A2 adenosine receptor agonist), but not by CPA (cyclopentyladenosine, selective A1 adenosine receptor agonist). Motor activity produced by ...

The effects of intraperitoneal injection of N6-cyclohexyladenosine (CHA, a selective adenosine A1 receptor agonist) and 8-cyclopenthyle-I-3-dimethylexanthine (CPT, a selective adenosine A1 receptor antagonist) on entorhinal cortex-kindled seizures were investigated. Fully entorhinal cortex-kindled rats received normal saline (control), CHA (0.06, 0.12 and 0.25 mg/kg) or CPT (0.06 and 0.12 mg/kg...

The influence of adenosine receptor agonists and antagonists on amphetamine-induced conditioned place preference (CPP) was examined in male Wistar rats. Selective adenosine A1 receptor agonist, CPA, significantly reduced the acquisition of CPP induced by amphetamine. NECA (A2/A1 adenosine receptor agonist) produced similar effect, but selective A2 adenosine receptor agonist CGS 21680, attenuate...

Background. Recent advances in adrenergic pharmacology have made possible the identification of a1-adrenergic receptor subtypes using the specific blockers chloroethylcionidine and WB 4101. Methods and Results. In the present study, we used these two blockers to determine the mechanisms responsible for automatic rhythms occurring during simulated ischemia and reperfusion of isolated canine Purk...

Adenosine is a vascular endothelial cell mitogen, but anti-mitogenic for aortic smooth muscle cells and fibroblasts when acting via the A2B adenosine receptor. However, we show that adenosine increases porcine coronary artery smooth muscle cell (CASMC) number, cellular DNA content, protein synthesis, and PCNA staining. RT-PCR analysis indicates that porcine CASMC express A1, A2A, A3, and barely...

Adenosine is arguably the most potent and widespread presynaptic modulator in the CNS, yet adenosine receptor signal transduction pathways remain unresolved. Here, we demonstrate a novel mechanism in which adenosine A1 receptor stimulation leads to p38 mitogen-activated protein kinase (MAPK) activation and contributes to the inhibition of synaptic transmission. Western blot analysis indicated t...