Abstract
Hot compresses in the lumbar region are empirically known to ameliorate patient complaints of constipation and abdominal fullness. We have previously shown that warming the lumbar skin increases the interdigestive migrating motor complex (IMC) of the stomach in humans. The activity of vagal nerves is decreased by warm stimulation, and the action of splanchnic sympathetic nerves is inhibitory on the gastric motility. Therefore, we have provided a hypothesis that vasoconstriction and redilatation in the abdominal arteries induced by lumbar skin warming activate IMC of the stomach. To confirm this hypothesis, we examined the effect of lumbar skin warming (42°C, 10 min) on diameters of the abdominal aorta and coeliac artery (DAA and DCA) in healthy humans, employing an ultrasound imaging of these arteries. In the test group with lumbar skin warming, DCA during stimulation did not differ from DCA at rest. However, DCA post-stimulation was increased by 17%. DAA was not affected by warming. In the time-matched control group without warm stimulation, both DCA and DAA remained unchanged. It is therefore concluded that lumbar skin warming causes vasodilatation of the coeliac artery. The timing of the increase in DCA well coincided with that of the increase in IMC previously reported. This shows that an increase in gastric blood flow and the activation of IMC are induced together by lumbar skin warming, although a possibility of vasoconstriction preceding vasodilatation is still to be explored. [Jpn J Physiol 54 Suppl:S241 (2004)]
