Several problems are associated with gastric resection, including the dumping syndrome, reflux esophagitis, and malabsorption. A better understanding of the pathophysiological changes will shed light on new and improved therapy. Serum levels of seven circulating gastrointestinal hormones following a standardized solid meal and a brief score of symptoms were evaluated in 10 patients after partial distal gastrectomy and 12 patients after total gastrectomy, both groups reconstructed by Billroth II anastomosis, and 9 age-matched healthy controls. Patients underwent resection for gastric cancer and were studied 45±10 months after surgery. At the time of study, the patients had adapted well to surgery and no longer exhibited the severe symptoms of dumping seen immediately post-operatively .In contrast, the total gastrectomy patients exhibited the symptoms of reflux esophagitis .The gastrointestinal hormone changes could be divided into three patterns; obtunded responses (gastrin, PP), normal release (motilin, GIP) and increased secretion (CCK, neurotensin, PYY). In these, the early reaction of neurotensin correlated with the scores of late dumping syndrome and reflux esophagitis. In the literature, many gastrointestinal hor mones have been shown to respond as an enhancement rather than adaptation . In other gastrointestinal hormones, secretin belonged to the obtunded type and enteroglucagon were classified in the increased type. However, pathophysiological significance of these hormonal changes remained uncertain. The late adaptive changes in gastrointestinal hormone secretion may help to compensate for loss of gastric motor function which accompanies gastric resection. On the other hand, these hormonal changes may exacerbate the esophageal reflux following gastrectomy.

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The effects of endothelial products on intracellular calcium ion concentrations ([Ca²⁺] _i) were investigated in the guinea-pig aorta. The perfusate of bradykinin-stimulated cultured endothelial cells relaxed aortic rings by -70%; it was reduced to -50% by nitroarginine, to -30% in high-K solution and remained unaltered by indomethacin. The perfusate elevated the cyclic GMP content in the muscle, which was inhibited by nitroarginine. In cultured aortic muscle cells, bradykinin elevated [Ca²⁺] _i with an initial transient and following sustained phase; the former was absent after treatment with cyclopiazonic acid while the latter was abolished in [Ca²⁺] _o-free medium. The perfusate lowered aortic [Ca²⁺] _i, and this action was weakened by nitroarginine and diminished in high-K solution. Therefore, the perfusate reduced aortic [Ca²⁺] _i with and without an increase in cyclic GMP production. These actions were sensitive to nitroarginine and high-K, respectively, suggesting that the perfusate contained at least two relaxants, EDRF and EDHF, with both lowering [Ca²⁺] _i in aortic muscle mainly by inhibiting Ca²⁺ influx.

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The HPC-1/syntaxin-1A antigen was originally identified as a neuron-specific membrane protein in the central nervous system. The presence of HPC-1 antigen in the nervous system of the fetal rat gastrointestinal tract was immunohistochemically demonstrated using the antibody against HPC-1 to clarify the role of this protein in the development of the enteric nervous system. Rat gastrointestinal tract from 14-, 16-, 18-, and 20-day fetuses and adults were immunohistochemically examined for HPC-1 antigen by light microscopy. Acetylcholinesterase (AchE) activity was also examined as a comparison. HPC-1 activity was first detected on 18th day of gestation. AchE activity was first detected at the Auerbach's plexus of the esophagus on the 16th day of gestation. The presence of HPC-1 in the developing rat intestine revealed that the HPC-1 antigen may be a good indicator for expressing the maturation of enteric nervous system in the development of the enteric nervous system.

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The relationship between relaxation produced by acetylcholine (ACh) or substance P (SP) and tissue cyclic GMP content was investigated in the isolated guinea-pig aorta. ACh and SP relaxed aortic rings precontracted with noradrenaline (NA) or high-K solution ([K⁺] _o=38.8mM), in an endothelium-dependent manner. The amplitude of relaxation was larger for SP than for ACh. Nitroarginine inhibited ACh-induced but not SP-induced relaxation in NA-contraction, while this chemical inhibited both ACh- and SP-induced relaxations in high-K contraction. The tissue cyclic GMP content was not changed by nitroarginine or by removal of endothelial cells, but was elevated by stimulation with NA, ACh or SP by a factor of about 3, 5 or 11 times, respectively. These actions of ACh or SP were endothelium-dependent, and were inhibited by nitroarginine and remained unaltered by high-K solution. Thus, ACh and SP relax muscles indirectly by releasing endothelial factors, and the former by releasing mainly an endothelium-derived relaxing factor (EDRF), and the latter by releasing EDRF and other unidentified factors. As the relaxing actions of the latter factors are inhibited by high-K solution with no relation to the production of cyclic GMP, an involvement of hyperpolarizing factor, possibly EDHF, is suggested.

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