[Easy method for emesis using rats].
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Animals↗
Biomedical subjects
Ryo Saito
Publications and source records attributed to Ryo Saito.
An axonemal dynein particularly important for flagellar movement at high viscosity. Implications from a new Chlamydomonas mutant deficient in the dynein heavy chain gene DHC9.
Ciliary and flagellar axonemes contain multiple inner arm dyneins of which the functional difference is largely unknown. In this study, a Chlamydomonas mutant, ida9, lacking inner arm dynein c was isolated and shown to carry a mutation in the DHC9 dynein heavy chain gene. The cDNA sequence of DHC9 was determined, and its information was used to show that >80% of it is lost in the mutant. Electron microscopy and image analysis showed that the ida9 axoneme lacked electron density near the base of the S2 radial spoke, indicating that dynein c localizes to this site. The mutant ida9 swam only slightly slower than the wild type in normal media. However, swimming velocity was greatly reduced when medium viscosity was modestly increased. Thus, dynein c in wild type axonemes must produce a significant force when flagella are beating in viscous media. Because motility analyses in vitro have shown that dynein c is the fastest among all the inner arm dyneins, we can regard this dynein as a fast yet powerful motor.
Amino Acid Sequence↗
Oral administration of freeze-dried kefir reduces intestinal permeation of and oral sensitization to ovalbumin in mice.
An increase in plasma ovalbumin concentrations after intragastric administration of ovalbumin was suppressed by concomitant freeze-dried kefir in BALB/c mice. Serum levels of ovalbumin-specific immunoglobulin G and proliferation of splenic mononuclear cells in mice immunized orally with ovalbumin were suppressed by feeding freeze-dried kefir. We propose that kefir reduces intestinal permeation of food antigen, which contributes to suppression of oral sensitization.
Administration, Oral↗
Roles of substance P and NK(1) receptor in the brainstem in the development of emesis.
The emetic response is primarily a protective reflex occurring in a wide variety of vertebrates in response to the ingestion of toxic compounds. The role of the nuclei in the brainstem, including the area postrema, nucleus tractus solitarius, the dorsal motor nucleus of the vagus, and the central pattern generator for vomiting, as well as the involvement of the abdominal visceral innervation relevant to the emetic reflex, have all been discussed by many researchers. The introduction of serotonin 5-HT(3)-receptor antagonists into clinical practice allowed for a dramatic improvement in the management of vomiting. However, vomiting still remains a significant problem. The mechanism of the emetic response is even more complicated than was first thought. This review attempts to bring together some of the evidence suggesting the roles of substance P and its receptor, neurokinin NK(1) receptor, in the brainstem nuclei in the development of emesis. Accordingly, NK(1)-receptor antagonists might represent novel drugs for the management of major types of emesis.
Animals↗
Effect of enzymatic modification of dietary wheat flour for reducing its allergenicity on oral sensitization to and intestinal absorption of ovalbumin.
Increase in plasma immunoglobulin G specific to orally administered ovalbumin in Brown Norway rats was retarded by feeding enzyme-treated wheat flour when compared with untreated flour. Because plasma ovalbumin concentrations after feeding ovalbumin tended to be lower in mice fed enzyme-treated flour than in those fed untreated flour, suppression of ovalbumin absorption may be relevant to retarded sensitization observed in rats.
Allergens↗
Roles of the central prostaglandin EP3 receptors in cardiovascular regulation in rats.
In this study, we examined the effects of an intracerebroventricular (i.c.v.) administration of prostaglandin E2 (PGE2) and of selective agonists for PGE2 receptor subtypes, EP1, EP2, EP3 and EP4, on central cardiovascular regulation and renal sympathetic nerve activity (RSNA) in urethane-anesthetized rats. The central administration of PGE2 (0.01-1.0 nmol) resulted in increases in blood pressure, heart rate (HR) and RSNA in a dose-dependent manner. Cardiovascular responses to PGE2 (0.5 nmol, i.c.v.) were attenuated by pretreatment with ganglionic and adrenoceptor blocking agents, but not with SC-19220 (20 nmol, i.c.v.), an EP1 receptor antagonist. An i.c.v. administration of the EP3 agonist ONO-AE-248 (50.0 nmol) resulted in an increase in RSNA with pressor and tachycardia responses, while administration of the EP2 agonist ONO-AE1-259 and the EP4 agonist ONO-AE1-329 caused transient hypotension and slight increases in HR and RSNA. The administration of the selective EP1 agonist ONO-DI-004 showed no effect. These results suggest that the central PGE2-induced activation of the sympathetic nerve activity with hypertension and tachycardia may depend on stimulation of the EP3 receptors in the central nervous system.
Adrenergic Fibers↗