The effects of vasodilators on the relaxation of guinea-pig aorta during acute recoil

PIEZORESISTIVE STRAIN SENSOR APPLICATION IN EVALUATION OF MOUSE AORTIC MEDIA CUSHIONS EFFECTIVENESS AND SPONTANEOUS MYOGENIC CONTRACTION

The aortic media realized Windkessel vessel functions and maintain sustained ventricle ejection balance during cardiac circle. Wheatstone bridge circuit piezoresistive strain sensor had desirable sensing properties to investigate aortic cushion features. In this study, Wheatstone bridge sensor was used to evaluate quick stretching-induced aortic efficient cushions and spontaneous myogenic contractions. Mice aortic specimens were loosely hooked and stabilized to [Formula: see text][Formula: see text]mm stainless steel pin and strain sensor, whereas the other side was hooked and shows increasing specimen length. Specimen isometric tension and rhythmic spontaneous myogenic contraction were recorded. Isometric tension and spontaneous myogenic response at initial length ([Formula: see text] and ultimate length ([Formula: see text] were evaluated. Aortic specimen significantly eliminated mechanical rigid oscillations. The recovery to baseline time was significantly shortened at [Formula: see text] ([Formula: see text][Formula: see text]ms and [Formula: see text] ms at [Formula: see text] and [Formula: see text], respectively, but [Formula: see text][Formula: see text]ms and [Formula: see text][Formula: see text]ms in no-load test). High Ca[Formula: see text] incubation prolonged the recovery time to baseline at [Formula: see text] and [Formula: see text] ([Formula: see text][Formula: see text]ms and [Formula: see text][Formula: see text]ms, respectively) and suggested Ca[Formula: see text] decreased efficient cushion. Moreover, strain sensor successfully recorded the enhanced rhythmic spontaneous myogenic contractions in isometric specimen. Wheatstone bridge circuit sensor reflected the significance of efficient cushions under mechanical preload, which absolutely captured rhythmic myogenic contractions of mice aortic specimen.

Contribution of 5-HT2A receptor in nematode infection-induced murine intestinal smooth muscle hypercontractility

BACKGROUND & AIMS

Enteric nematode infection induces a smooth muscle hypercontractility that depends on interleukin (IL)-4 and IL-13 activation of the signal transducer and activator of transcription (STAT) 6. Serotonin (5-HT) is involved in the physiologic regulation of gut function. The present study investigated the contribution of 5-HT and its receptors in nematode-induced intestinal smooth muscle hypercontractility.

METHODS

Mice were infected with Nippostrongylus brasiliensis (N brasiliensis) or Heligmosomoides polygyrus (H polygyrus) or injected intravenously with IL-13. Segments of jejunum were suspended in organ baths, and smooth muscle responses to 5-HT were determined in the presence or absence of specific 5-HT antagonists. IL-4, IL-13, and 5-HT receptor messenger RNA expressions were determined by real-time quantitative polymerase chain reaction.

RESULTS

5-HT evoked a modest contraction of smooth muscle in wild-type (WT) mice that was unaltered by the 5-HT2A antagonist ketanserin. N brasiliensis infection induced a smooth muscle hypercontractility to 5-HT that was abolished by 5-HT(2A) antagonists but not by other 5-HT antagonists. Infection-induced up-regulation of 5-HT2A expression was correlated with the smooth muscle hypercontractility to 5-HT. The infection-induced up-regulation of 5-HT2A in WT mice was observed also in IL-4(-/-) mice but was not seen in IL-13(-/-) or STAT6(-/-) mice. In addition, smooth muscle responses to 5-HT and 5-HT2A expression in WT mice were also enhanced by IL-13 or H polygyrus infection.

CONCLUSIONS

These data show that 5-HT2A is one of the molecules downstream from STAT6 activation that mediates changes in smooth muscle function. 5-HT2A represents a novel therapeutic target for modulating immune-mediated effects on intestinal motility.

Therapeutic Potentials of Sarpogrelate in Cardiovascular Disease*

In view of the pivotal role of serotonin (5-HT) in a wide variety of cardiovascular disorders, extensive effort has been made to develop different types of 5-HT receptor antagonists for therapeutic use. On the basis of experimental studies, this article is focused on the potentials of sarpogrelate, a specific 5-HT2A receptor antagonist as an antiplatelet, antithrombotic, antiatherosclerotic and antianginal agent. The major effects of sarpogrelate are due to the inhibition of 5-HT-induced platelet aggregation and smooth muscle cell proliferation. This agent was found to attenuate the 5-HT-mediated increase in intracellular Ca2+ and ischemia-reperfusion injury in the heart. Sarpogrelate has been found to have beneficial effects in peripheral vascular disease, restenosis after coronary stenting, pulmonary hypertension, acute and chronic myocardial infarction.