Molecular cloning of a novel putative G‐protein coupled receptor expressed during rat spermiogenesis

Abstract

A cDNA clone encoding a novel putative G-protein coupled receptor has been isolated from a rat testis cDNA library using a PCR-amplified cDNA fragment as a hybridization probe. Northern blot anaIysis reveals that a corresponding 1.5 kb mRNA is exclusively cxpresscd in testis. By in situ hybridization experiments this mRNA has been localized in spermatocytes and spermatids but not in spermatogonia. Lcydig or sertoli cells. Ontogenic studies show that expression of the receptor-encoding mRNA and sexual maturation are correlated reaching highest levels during the second and third months. Although the ligand for this receptor has not yet been identified. this receptor may play a role during reproduction.G-protein coupled receptor; Rat testis; Spermiogencsis

Adenosine A3 receptor stimulation and cerebral ischemia

“…Very recently a novel adenosine receptor subtype (A 3 ) has been identified in the rat (Meyerhof et al, 1991;Zhou et al, 1992), and similar receptors have been cloned from both human (Salvatore et al, 1993) and sheep brain cDNA libraries . It has been shown that activation of adenosine A 3 receptors causes inhibition of adenylate cyclase and stimulation of phospholipase C (Zhou et al, 1992;Ramkumar et al, 1993).…”

A2B adenosine receptors mediate relaxation of the pig intravesical ureter: adenosine modulation of non adrenergic non cholinergic excitatory neurotransmission

“…These receptors are coupled to an inhibitory G protein (Meyerhof et al, 1991;Zhou et al, 1992). N 6 -(3-iodobenzyl)-adenosine-5'-N-methylcarboxamide (IB-MECA) has been reported as a selective A 3 -receptor agonist (Jacobson et al, 1993;Gallo-RodrõÂ guez et al, 1994).…”

Activation and desensitization of rat A3-adenosine receptors by selective adenosine derivatives and xanthine-7-ribosides

“…Activation of the high-affinity A 2A receptors and the low-affinity A 2B receptors results in activation of adenylyl cyclase. The A 3 receptor is the most recently discovered subtype [Ali et al, 1990;Meyerhof et al, 1991;Zhou et al, 1992]. It has been shown to be coupled to the inhibition of adenylyl cyclase when the receptor is expressed in Chinese hamster ovary (CHO) cells [Zhou et al, 1992] and to activation of phospholipase C (PLC) both in the rat RBL-2H3 mast cell line and in brain slices [Ali et al, 1990;Abbracchio et al, 1995;Shin et al, 1996].…”