Chromic acid oxidation of tazettine.
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Alkaloids↗
Biomedical subjects
H Yajima
Publications and source records attributed to H Yajima.
Morphine-like analgesic actions of enkephalin-like peptides containing the Tyr-Arg unit.
The analgesic actions of some synthetically prepared peptides having the Tyr-D-Arg unit at the N terminal portion of met- and leu-enkephalin were measured by the intra-cisternal injection method in mice. Among them, Tyr-D-Arg-Gly-Phe (DR-4) induced the most potent naloxone-reversible analgesia and was also effective by s.c. injection. DR-4 showed the good affinity to mu-receptor, and the resistance to the enzymatic degradation.
Animals↗
Effect of synthetic porcine gastrin-releasing peptide on plasma levels of immunoreactive cholecystokinin pancreatic polypeptide and gastrin in dogs.
This study was conducted to determine if synthetic porcine gastrin-releasing peptide (GRP) stimulates the release of immunoreactive cholecystokinin (CCK), pancreatic polypeptide (PP) and gastrin in dogs. Three doses (0.01, 0.1 and 0.5 micrograms/kg-hr) of synthetic porcine GRP were administered intravenously to six conscious dogs. Synthetic porcine GRP stimulated the release of each hormone in a dose-related manner. The effect of GRP on the response of gastrin was greater than its effect on CCK and PP responses. This study indicates that the biological action of synthetic porcine GRP is similar to the bombesin, an amphibian peptide shown previously to stimulate the release of gastrointestinal peptides.
Animals↗
Possible mechanisms of positive inotropic action of synthetic human calcitonin gene-related peptide in isolated rat atrium.
The effect of synthetic human calcitonin gene-related peptide (hCGRP) on the isolated and electrically driven left atria of rats were investigated. The peptide at concentrations of 3 X 10(-9)-3 X 10(-7) M produced positive inotropic effects on the left atria in a dose-dependent manner. Verapamil (10(-5) M) and adenosine (10(-4) M) reduced the positive inotropic effect of hCGRP at concentrations of 3 X 10(-9) and 3 X 10(-8) M, but not at that of 3 X 10(-7) M. Ouabain (5 X 10(-5) M) inhibited the effect of hCGRP in concentrations of 3 X 10(-7) and 3 X 10(-8) M, but not in that of 3 X 10(-9) M. Simultaneous pretreatment with verapamil (10(-5) M) and ouabain (5 X 10(-5) M) suppressed the positive inotropy by hCGRP at all concentrations tested. On the other hand, tetrodotoxin (10(-6) M) potentiated only the positive inotropic effect of 3 X 10(-7) M hCGRP. Metoprolol (10(-7) M) and theophilline (10(-3) M) did not affect the inotropic effect of hCGRP. These results suggest that the positive inotropic effect of hCGRP is not mediated by beta-adrenoceptors but by two distinct mechanisms of action, which was inhibited by verapamil but not by ouabain (facilitation of Ca++ influx in lower concentrations of hCGRP) and which was blocked by ouabain but not by verapamil and potentiated by tetrodotoxin (inhibition of Na+/Ca++ exchange mechanism at higher concentrations of hCGRP).
Adenosine↗
Effects of synthetic kassinin on splanchnic circulation and exocrine pancreas in dogs.
Effects of intravenously administered synthetic kassinin on splanchnic circulation and exocrine pancreatic secretion were examined in six anesthetized dogs. Kassinin caused dose-related increases in the blood flow in superior mesenteric artery and portal vein, and produced an initial increase followed by a decrease in pancreatic blood flow, but did not affect the exocrine pancreatic secretion. This study demonstrates that kassinin affects splanchnic blood flow in dogs, and suggests that kassinin or a kassinin-like substance functions as a neuropeptide controlling the splanchnic circulation in mammalian species.
Animals↗
Calcitonin gene-related peptide increases in the dorsal root ganglia of adjuvant arthritic rat.
We examined the effect of adjuvant arthritis on the content of immunoreactive calcitonin gene-related peptide (iCGRP) in the dorsal root ganglia at L4-L6 levels and the spinal cord at a lumbar level in rats. Arthritis was induced by inoculating adjuvant into both hind-paws twice at a 10 day interval. In the arthritic rats 15 days after the first inoculation (day 15), the content of iCGRP was significantly increased in the dorsal root ganglia, with no change in the dorsal and ventral horns. The content in the dorsal root ganglia was still high on day 26 and had decreased by day 40. An intrathecal injection of colchicine (0.2 mg, 18 hr before killing) enhanced the increase of iCGRP in the dorsal root ganglia and decreased it in the dorsal horn of arthritic rats, although in noninoculated rats such treatment produced no significant changes in the content of iCGRP in both regions. The arthritis-induced increase in the content of iCGRP in the dorsal root ganglia was significantly reduced after treatment with the antiinflammatory analgesic, diclofenac sodium, in a dose of 3 mg/kg/day, PO for 10 days. Swelling and hyperalgesia in the hind-paw were depressed after such treatment. These results suggest that adjuvant arthritis with long-lasting inflammation with pain facilitates the turnover, especially biosynthesis, of CGRP in primary afferent neurons.
Animals↗
Effects of synthetic human pancreastatin on pancreatic secretion and blood flow in rats and dogs.
Effects of synthetic human pancreastatin-52 and human pancreastatin-29 on pancreatic secretion and blood flow were examined in rats and dogs. Synthetic human pancreastatin-52 and human pancreastatin-29 were equally potent in suppressing the release of amylase stimulated by cholecystokinin in rats in vivo. However, neither human pancreastatin-52 nor human pancreastatin-29 altered basal and cholecystokinin-stimulated amylase release from isolated dispersed rat pancreatic acini. In studies in dogs, human pancreastatin-29 suppressed releases of amylase and protein stimulated by cholecystokinin, but did not alter pancreatic blood flow. These results suggest that the inhibitory effects of pancreastatin on pancreatic secretion do not involve a direct action on pancreatic acinar cells nor alteration of pancreatic blood flow. Pancreastatin probably is important in regulating exocrine pancreatic secretions as well as endocrine pancreatic secretions.
Amylases↗
Biological activity of neurotensin and its C-terminal partial sequences.
A hypothalamic tridecapeptide, neurotensin, and its C-terminal partial sequences down to the dipeptide were synthesized. These peptides were assayed for smooth muscle contracting and blood pressure lowering properties using preparations of isolated stomach fundus, uterus and duodenum of the rat, isolated guinea pig ileum and rabbit carotid artery. Sequences of 6 or more terminal amino acids produced a strong stomach fundus contracting effect, the potencies of the fragments being approximately equivalent to or slightly more than that of the parent tridecapeptide. These fragments also elicited the ileum contracting activity, but the potencies were only one fifth to one tenth that of neurotensin. The tetra- or dipeptide hardly stimulated either the fundus or the ileum. The stimulating effect on the uterus or relaxing effect on the duodenum of neurotensin was not consistent. Rabbit blood pressure was lowered markedly by neurotensin and weakly by its dodecapeptide. From these results, the arginine or arginine-arginine residue down to the C-terminal leucine appears to be essential for the smooth muscle contracting activity of neurotensin. The full length sequence may be needed for the hypotensive effect.
Amino Acid Sequence↗
Effects of motilin and octapeptide of cholecystokinin on antral and duodenal myoelectric activity in the interdigestive state and during inhibition by secretin and gastric inhibitory polypeptide.
In conscious dogs prepared with gastric cannulae and antral and duodenal electrodes, intravenous administration of synthetic porcine motilin and CCK-OP in varying doses resulted in significant increases in the mean percent frequency of spike potentials on slow waves. Motilin was a more potent stimulant than CCK-OP. Motilin-stimulated spike potentials in both antrum and duodenum were significantly suppressed by either natural porcine secretin or synthetic porcine GIP. Secretin suppressed the spike potentials of the antrum stimulated by CCK-OP but not those of the duodenum. The spike potentials stimulated by CCK-OP could not be suppressed by GIP in the dosages employed.
Action Potentials↗
Mucoepidermoid carcinoma of the trachea with airway hyperresponsiveness.
We report a case of mucoepidermoid carcinoma of the trachea in a 23-year-old pregnant female in her 39th week. The patient had cough and wheezing in the early morning for 9 months before admission. No abnormalities were detected on a chest roentgenogram. At Caesarean section, fiberscopy revealed a polypoid lesion narrowing the trachea. The pathologic diagnosis made from the biopsy specimen obtained was low-grade mucoepidermoid carcinoma and the lesion was resected. Airway hyperresponsiveness was shown before resection with airflow limitation, however, airway reactivity and airflow limitation improved 1 year after resection.
Adult↗