Lower esophageal sphincter relaxation is associated with increased cyclic XXXX content.

@entity268 @entity6708 @entity3549 @entity935 @entity1022 @entity1854 @entity377 @entity8613 @entity3044
Experiments were conducted to determine whether relaxation of the opossum isolated lower esophageal sphincter (LES), induced by electrical field stimulation (EFS) or various pharmacological agents, is associated with changes in cyclic @entity377 content. EFS relaxed the LES in a frequency-dependent manner with 0.7 Hz producing half-maximal relaxation. Control tissues and tissues stimulated at various frequencies were clamp-frozen and assayed for cyclic @entity377 content. EFS had no effect on @entity268 ( @entity268 ) content but increased @entity6708 ( @entity6708 ) content in a frequency-dependent manner. @entity1022 eliminated both the relaxation and @entity6708 accumulation in response to EFS. @entity3549 ( @entity3549 ) relaxed the LES with an EC50 of 0.1 microM. In contrast to the results with EFS, @entity3549 enhanced @entity268 content but had no effect on @entity6708 content. Relaxation of the LES produced by @entity1854 or atriopeptin II was accompanied by an increase in @entity6708 accumulation, whereas @entity3044 - and @entity935 -induced relaxation was accompanied by an increase in @entity268 content. The data indicate that, depending on the stimulus, increases in either @entity268 or @entity6708 content can accompany LES relaxation. These results are consistent with the proposed role of @entity8613 as second messengers mediating LES relaxation.
