Search results for "A1 receptor"

Effects of the LPA1 Receptor Deficiency and Stress on the Hippocampal LPA Species in Mice

2019

Lysophosphatidic acid (LPA) is an important bioactive lipid species that functions in intracellular signaling through six characterized G protein-coupled receptors (LPA1-6). Among these receptors, LPA1 is a strong candidate to mediate the central effects of LPA on emotion and may be involved in promoting normal emotional behaviors. Alterations in this receptor may induce vulnerability to stress and predispose an individual to a psychopathological disease. In fact, mice lacking the LPA1 receptor exhibit emotional dysregulation and cognitive alterations in hippocampus-dependent tasks. Moreover, the loss of this receptor results in a phenotype of low resilience with dysfunctional coping in res…

Adenosine negatively regulates duodenal motility in mice: role of A1 and A2a receptors .

2011

A1 receptor-mediated modulatory effects of adenosine on the contractility in mouse ileum: characterization of signal transduction pathway

2008

Inhibitory responses to exogenous adenosine in murine proximal and distal colon”

2006

The aims of the present study were firstly, to characterize pharmacologically the subtypes of P(1) purinoreceptors involved in the inhibitory effects induced by exogenous adenosine in longitudinal smooth muscle of mouse colon, and secondly, to examine differences in the function and distribution of these receptors between proximal and distal colon. Adenosine (100 microM-3 mM) caused a concentration-dependent reduction of the amplitude of spontaneous contractions in the proximal colon, and muscular relaxation in the distal colon. In the proximal colon, adenosine effects were antagonized by a selective A(1) receptor antagonist, 1,3-dipropyl-8-cyclopentylxanthine (DPCPX, 10 nM), but were not m…

Endogenous adenosine inhibits hippocampal CA1 neurones: further evidence from extra- and intracellular recording.

1988

Extracellular and intracellular recordings from CA1 pyramidal neurones of rats in vitro were used to study the effects of endogenous and exogenously applied adenosine. The adenosine receptor antagonist, caffeine, enhanced the intracellular recorded e.p.s.p.-i.p.s.p. sequence evoked by stimulation of the stratum radiatum which is antagonized by exogenous adenosine. The late, potassium dependent i.p.s.p. was not antagonized. The adenosine uptake inhibitor, nitrobenzylthioinosine (NBTI), mimicked the effects of exogenously applied adenosine. The effects of NBTI and of exogenously applied adenosine were antagonized by caffeine in the same manner. Exposure to adenosine deaminase enhanced the evo…

A1 receptors mediate adenosine inhibitory effects in mouse ileum via activation of potassium channels.

2008

Abstract Aims We investigated the effects induced by exogenous adenosine on the spontaneous contractile activity of the longitudinal muscle of a mouse ileum, the receptor subtypes activated, the involvement of enteric nerves and whether opening of K + channels was a downstream event leading to the observed effects. Main methods Mechanical responses of the mouse ileal longitudinal muscle to adenosine were examined in vitro as changes in isometric tension. Key findings Adenosine caused a concentration-dependent reduction of the spontaneous contraction amplitude of the ileal longitudinal muscle up to its complete disappearance. This effect induced was markedly reduced by an A 1 receptor antago…

An electrophysiological study of the ontogenesis of adenosine receptors in the CA1 area of rat hippocampus

1990

Abstract The depressant effect of adenosine (Ad) was studied electrophysiologically in hippocampal slices from 5-, 10-, 15-, 20-, 30- and 120-day-old rats. Ad (10μM) depressed the field EPSP in CA1 to the same extent in all age groups. Caffeine (Caf), an Ad receptor antagonist, enhanced and nitrobenzylthioinosine (NBI), an Ad uptake blocker, depressed the field EPSP. Both these effects were, however, less prominent in slices from younger animals, a finding consistent with lower extracellular levels of endogenous Ad in neonatal rats.

Calcium and increase excitability promote tolerance against anoxia in hippocampal slices.

1999

We have previously demonstrated that anoxic preconditioning (APC) protects against a subsequent otherwise 'lethal' anoxic insult in hippocampal slices. Tested here are two hypotheses: (a) APC requires calcium to improve electrical recovery in hippocampal slices; and (b) mild excitation promotes preconditioning neuroprotection. Control hippocampal slices were given a single 'test' anoxic insult followed by reoxygenation. Experimental slices were preconditioned by three short anoxic insults of 1 min separated by 10 min of reoxygenation. At 30 min after the third 'conditioning' insult, slices underwent a 'test' anoxic insult [1 min of anoxic depolarization (AD)], and then slices were reoxygena…

Adenosine negatively regulates duodenal motility in mice: role of A1 and A2A receptors

2011

BACKGROUND AND PURPOSE Adenosine is considered to be an important modulator of intestinal motility. This study was undertaken to investigate the role of adenosine in the modulation of contractility in the mouse duodenum and to characterize the adenosine receptor subtypes involved. EXPERIMENTAL APPROACH RT-PCR was used to investigate the expression of mRNA encoding for A1, A2A, A2B and A3 receptors. Contractile activity was examined in vitro as changes in isometric tension. KEY RESULTS In mouse duodenum, all four classes of adenosine receptors were expressed, with the A2B receptor subtype being confined to the mucosal layer. Adenosine caused relaxation of mouse longitudinal duodenal muscle; …