Anesthesia and analgesia
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Anesthesia and analgesia · Jun 2008
Expression of adenosine A 2A receptors in the rat lumbar spinal cord and implications in the modulation of N-methyl-d-aspartate receptor currents.
The presence of A(2A) receptors in the dorsal horn of the spinal cord remains controversial. At this level, activation of N-methyl-d-aspartate (NMDA) receptors induces wind-up, which is clinically expressed as hyperalgesia. Inhibition of NMDA receptor currents after activation of A(2A) receptors has been shown in rat neostriatal neurons. In this study, we sought to establish the presence of adenosine A(2A) receptors in the lamina II of the rat lumbar dorsal horn neurons and investigated whether the activation of A(2A) receptors is able to modulate NMDA receptor currents. ⋯ These results demonstrate the presence of A(2A) receptor on neurons from the substantia gelatinosa of the rat lumbar dorsal horn and the inhibition of NMDA-induced currents by the application of a selective A(2A) receptor agonist. Therefore, A(2A) receptor ligands could modulate pain processing at the spinal cord level.
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Anesthesia and analgesia · Jun 2008
Rho-kinase inhibitors augment the inhibitory effect of propofol on rat bronchial smooth muscle contraction.
Airway smooth muscle contraction is not caused by the increase in intracellular Ca(2+) ([Ca(2+)](i)) alone because agonist stimulation increases tension at the same [Ca(2+)](i) (increase in Ca(2+) sensitivity). The small G protein Rho A and Rho-kinase (ROCK) play important roles in the regulation of Ca(2+) sensitivity. In this study, we investigated the effects of three ROCK inhibitors (fasudil, Y-27632, and H-1152) on rat airway smooth muscle contraction and the effects of ROCK inhibitors on propofol-induced bronchodilatory effects. ⋯ ROCK inhibitors, especially H-1152, can attenuate the contraction of rat airway smooth muscle. The combined use of ROCK inhibitors and propofol causes greater relaxation.