Purines and pyrimidines are indispensable molecules of life; they fundamental for genetic code bioenergetics. From the very early evolution life purines have acquired meaning damage-associated extracellular signaller purinergic receptors emerged in unicellular organisms. Ancestral purinoceptors P2X-like ionotropic ligand-gated cationic channels showing 20–40% homology with vertebrate P2X recept...

The pre- and postsynaptic actions of exogenously applied ATP were investigated in intact and dissociated parasympathetic neurones of rat submandibular ganglia. Nerve-evoked excitatory postsynaptic potentials (EPSPs) were not inhibited by the purinergic receptor antagonists, suramin and pyridoxal-phosphate-6-azophenyl-2',4'-disulphonic acid (PPADS), or the desensitising agonist, alpha,beta-methy...

Luminal acidity is a physiological challenge in the foregut, and acidosis can occur throughout the gastrointestinal tract as a result of inflammation or ischemia. These conditions are surveyed by an elaborate network of acid-governed mechanisms to maintain homeostasis. Deviations from physiological values of extracellular pH are monitored by multiple acid sensors expressed by epithelial cells a...

Data are not yet available for ATP, but using thrombin as an agonist it has been shown that the initial transient rise in [Ca2+Ii is both necessary and sufficient to account for PGI, release (Hallam et al., 1988). ATP, like thrombin, also opens receptor-operated Ca? +-selective channels in endothelial cells (Hallam & Pearson, 1986) and these may be more important for EDRF production. Similar AT...

tk;1Adenosine plays a role in the control of water and electrolyte reabsorption in the distal tubule. As the distal convoluted tubule is important in the regulation of renal Mg(2+) balance, we determined the effects of adenosine on cellular Mg(2+) uptake in this segment. The effect of adenosine was studied on immortalized mouse distal convoluted tubule (MDCT) cells, a model of the intact distal...