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N Morii

Publications and source records attributed to N Morii.

106 records · Page 6Linked to original sources
PubMed1986

Centrally administered leumorphin possesses potent depressor activity in conscious rats.

The effect of intracerebroventricular (i.c.v.) administration of leumorphin on basal blood pressure and angiotensin II (AII)-stimulated increase in blood pressure was examined in conscious unrestrained rats. The i.c.v. injection of leumorphin (0.06 and 0.6 nmol) elicited significant depressor effect. The i.c.v. administration of leumorphin with AII (0.1 nmol) significantly attenuated the AII-induced pressor response and, furthermore, lowered blood pressure below the basal level. These results suggest that leumorphin is involved in the central control of blood pressure.

Angiotensin II↗
PubMed1985

Specific binding activities and cyclic GMP responses by atrial natriuretic polypeptide in kidney epithelial cell line (LLC-PK1).

Receptor binding activities and cyclic GMP responses by alpha-human atrial natriuretic polypeptide (alpha-hANP) and its fragments were studied in a kidney epithelial cell line (LLC-PK1). Binding of 125I-alpha-hANP to the cells at 0 degrees C was saturable, time-dependent and reversible, indicating the presence of a single class of binding sites. alpha-hANP (7-23)NH2 fragment inhibited most effectively the specific binding of 125I-alpha-hANP to the LLC-PK1 cells, followed by alpha-hANP (17-28) and alpha-hANP (8-22), while alpha-hANP (1-6) and alpha-hANP (24-28) did not. alpha-hANP stimulated the formation of cyclic GMP in the LLC-PK1 cells dose-dependently. Although no fragments of alpha-hANP used were effective for cyclic GMP formation in the LLC-PK1 cells, alpha-hANP (7-23) NH2 antagonized the action of alpha-hANP on cyclic GMP formation. These data suggest that the LLC-PK1 cells retain specific receptors for atrial natriuretic polypeptide (ANP) and respond to ANP by stimulating cyclic GMP formation, and therefore this cell line may be useful for studying the mechanism of action for ANP in renal tubular cells.

1-Methyl-3-isobutylxanthine↗
PubMed1985

Specific receptors for atrial natriuretic polypeptide on basolateral membranes isolated from rat renal cortex.

The binding of alpha-human atrial natriuretic polypeptide (alpha-hANP) to brush border and basolateral membranes isolated from the rat renal cortex was studied at 0 degree C by a rapid filtration technique. Specific binding of 125I-alpha-hANP to basolateral membranes reached a steady state at 4 hr. The binding to brush border membranes was maximal at 5-15 min and then rapidly decreased. The analysis of incubation mixtures with basolateral membranes revealed little degradation of 125I-alpha-hANP during the 4-hr incubation, while there was extensive degradation of the ligand with brush border membranes during the 30-min incubation. High affinity binding of 125I-alpha-hANP was demonstrated on basolateral membranes but not on brush border membranes. These data suggest that specific receptors for alpha-hANP are localized on basolateral membranes of the renal cortex.

Animals↗
PubMed1985

Alpha-human atrial natriuretic polypeptide is released from the heart and circulates in the body.

In order to clarify whether or not atrial natriuretic polypeptides are hormones in man, we have measured plasma alpha-human atrial natriuretic polypeptide (alpha-hANP)-like immunoreactivity (alpha-hANP-LI) with or without extraction procedure. alpha-hANP-LI was detected in plasma extracts from all 5 normal subjects and 7 patients with heart diseases. The alpha-hANP-LI concentration in normal peripheral plasma was 37.7 +/- 7.0 pg/ml (mean +/- SE). Plasma concentrations of alpha-hANP-LI in the coronary sinus obtained by cardiac catheterization were 3 to 10 times higher than those in the peripheral vein, inferior vena cava, right atrium, pulmonary artery and aorta. High performance gel permeation chromatography coupled with a radioimmunoassay (RIA) for alpha-hANP revealed that alpha-hANP-LI in normal peripheral plasma eluted at the position corresponding to that of authentic alpha-hANP without detectable amounts of high molecular weight forms. alpha-hANP-LI extracted from plasma taken from the coronary sinus of two patients also showed a single peak of alpha-hANP-LI co-eluting with alpha-hANP. In contrast, not only alpha-hANP but gamma-hANP and beta-hANP, high molecular weight forms, were present in the human atrial tissue. These results indicate that alpha-hANP is the predominant form of alpha-hANP-LI in human plasma and that this form generated in the atrial cardiocytes is preferentially released from these cells and circulates in the body.

Adult↗
PubMed1985

Existence of atrial natriuretic polypeptide in kidney.

Using a specific radioimmunoassay (RIA) for alpha-atrial natriuretic polypeptide (alpha-ANP), we have demonstrated the presence of alpha-rat ANP-like immunoreactivity (alpha-rANP-LI) in the rat kidney which is considered to be a target organ for atrial natriuretic polypeptides released from the heart. Most of alpha-rANP-LI was localized in the cortex. High performance gel permeation chromatography coupled with the RIA revealed that renal alpha-rANP-LI was eluted at the position of a low molecular weight form corresponding to alpha-rANP without detectable amounts of high molecular weight forms. This is in contrast to the observation that gamma-rANP, a high molecular weight form of 13k daltons, is the dominant form of alpha-rANP-LI in the rat atrium. In water-deprived rats, the concentration and content of alpha-rANP-LI in the kidney showed a significant decrease compared with control rats. In addition, the alpha-rANP-LI concentration and content in this organ revealed a substantial decrease after perfusion with physiological saline. These results indicate the existence of atrial natriuretic polypeptide (ANP) in the kidney and suggest that part of renal ANP may originate from the heart.

Animals↗
PubMed1985

Occurrence of atrial natriuretic polypeptide in brain.

In order to determine whether or not atrial natriuretic polypeptides (ANPs) exist in the brain, we have studied extracts from the rat brain using a specific radioimmunoassay (RIA) for alpha-atrial natriuretic polypeptide. The presence and widespread distribution of alpha-rat ANP-like immunoreactivity (alpha-rANP-LI) have been demonstrated in the rat brain. The highest concentration of alpha-rANP-LI (20-22 ng/g) is in the hypothalamus and the septum. Moderate concentrations of alpha-rANP-LI (2-8 ng/g) are also found in the midbrain, cerebral cortex, olfactory bulb, thalamus, pons-medulla and hippocampus. High performance gel permeation chromatography coupled with the RIA revealed that alpha-rANP-LI found in the rat brain consists of three components eluting at the positions of gamma-rat ANP (gamma-rANP), beta-rat ANP (beta-rANP) and alpha-rANP, respectively. Among these a low molecular weight form of alpha-rANP-LI emerging at the elution position corresponding to alpha-rANP is predominant in the rat brain. This is in contrast to the finding that gamma-rANP, a high molecular weight form of 13k daltons is the dominant form of alpha-rANP-LI in the rat atrium. These results clearly show that there exists a widespread neural system containing ANPs in the brain.

Animals↗
PubMed1985

Immuohistochemical demonstration of alpha-atrial natriretic plypeptide-containing neurons in the rat brain.

Using the immunoperoxidase technique in conjunction with specific antisera to alpha-atrial natriuretic polypeptide (alpha-ANP), it was shown that immunoreactive cell bodies and varicose fibers are widely distributed throughout the rat brain. The highest concentrations of alpha-ANP-containing neuronal cell bodies and fibers were found in the hypothalamus and septum. This result confirms the radioimmunological determination of alpha-ANP immunoreactivity in the rat brain.

Animals↗
PubMed1985

Leumorphin in human brain.

Porcine leumorphin, a putative opioid peptide corresponding to amino acid residues 228-256 of preproenkephalin B has been demonstrated to exist in the porcine neurointermediate pituitary. A recent study on the sequence analysis of genomic DNA of human preproenkephalin B has shown that human leumorphin differs in 3 amino acid residues from porcine leumorphin. In order to clarify whether leumorphin is an endogenous opioid peptide in man, we have studied its existence and regional distribution in the human brain using a radioimmunoassay (RIA) for leumorphin. Reverse-phase HPLC and high performance gel permeation chromatography coupled with the RIA for leumorphin revealed that human leumorphin existed together with rimorphin (dynorphin B) in water extracts of the human brain. Leumorphin-like immunoreactivity (-LI) and dynorphin-LI distributed in parallel throughout the brain. These results indicate that leumorphin is a novel endogenous opioid peptide in man.

Animals↗
PubMed1985

Atrial natriuretic polypeptide: topographical distribution in the rat brain by radioimmunoassay and immunohistochemistry.

The widespread distribution of neurons containing alpha-atrial natriuretic polypeptide-like immunoreactivity in the rat brain was demonstrated using radioimmunoassay and immunohistochemistry in conjunction with specific antisera. The highest concentrations of alpha-atrial natriuretic polypeptide-like immunoreactivity were in the hypothalamus and septum, with low but still appreciable concentrations in the mesencephalon, cerebral cortex, olfactory bulb and thalamus by radioimmunoassay. Immunohistochemical studies clearly showed that the perikarya of immunoreactive neurons are most prevalent in the ventral part of the lateral septal nucleus, periventricular preoptic nucleus, bed nucleus of the stria terminalis, periventricular and dorsal parts of the paraventricular hypothalamic nucleus, ventromedial nucleus, dorsomedial nucleus, arcuate nucleus, median mamillary nucleus, supramamillary nucleus, zona incerta, medial habenular nucleus and the periaqueductal grey matter. Scattered neurons were seen in the cingulate cortex, endopiriform nucleus, lateral hypothalamic area, and pretectal and dorsal thalamic areas. In addition to the areas mentioned above, high concentrations of immunoreactive varicose fibers were seen in the glomerular layer of the olfactory bulb, external layer of the median eminence, central to paramedian parts of the interpeduncular nucleus and the paraventricular hypothalamic nucleus. The globus pallidus, medial and central amygdaloid nuclei, dorsal raphe, dorsal parabrachial nucleus, locus coeruleus, vagal dorsal motor nucleus, solitary nucleus and some circumventricular organs, including the subfornical organ and organum vasculosum laminae terminalis, contained considerable numbers of immunoreactive varicose fibers. In dehydrated rats and homozygous Brattleboro rats, the pattern of alpha-atrial natriuretic polypeptide-immunoreactive neurons and varicose fibers was qualitatively similar to that seen in normal conditioned rats. This study gives an atlas of the distribution of the alpha-atrial natriuretic polypeptide-containing neuronal system in the rat brain and provides the groundwork for studying the influence of this new peptide on various brain functions.

Animals↗
PubMed1985

Accelerated natriuresis induced by synthetic atrial natriuretic polypeptide in spontaneously hypertensive rats.

Effects of synthetic alpha human atrial natriuretic polypeptide (alpha-hANP) on diuresis, natriuresis and mean arterial blood pressure (MAP) were compared between 4-5 month-old male spontaneously hypertensive rats (SHR) and Wistar-Kyoto rats (WKY) under ether anesthesia. In both groups, the peptide injected (0.5 micrograms/100g body weight, i.v.) caused potent (about ten fold), rapid and short-acting (for 15 min) increases in sodium (Na+) and chloride excretions and also an increase in urine flow and potassium excretion with lesser magnitude. Although ratios of the maximum response to basal value were much the same, net increases in urine flow and Na+ output were significantly greater in SHR than in WKY. As to the effect on MAP, a rapid (within 2 min) fall observed in the two groups. These results suggest that the atrial natriuretic peptide may be involved in the altered regulatory mechanism of fluid and electrolyte balance in SHR models with genetic hypertension.

Animals↗
PubMed1984

Radioimmunoassay for alpha-human and rat atrial natriuretic polypeptide.

Using a synthetic common carboxy-terminal fragment of alpha-human atrial natriuretic polypeptide (alpha-hANP) and alpha-rat atrial natriuretic polypeptide (alpha-rANP), we have produced an antiserum for alpha-ANP(17-28) and established a radioimmunoassay (RIA) for alpha-ANP that recognizes alpha-hANP and alpha-rANP equally. High performance gel permeation chromatography coupled with the RIA revealed that alpha-hANP-like immunoreactivity (alpha-hANP-LI) in the human atrium consists of three major components, gamma-hANP, alpha-hANP and another. On the other hand, alpha-rANP-LI in the rat atrium comprised at least two components, 13K alpha-rANP-LI and 3K-5K alpha-rANP-LI, which were presumably gamma-rANP and beta-rANP, respectively. Thus, considerable amounts of gamma-hANP and gamma-rANP are present in human right auricles and rat atria, respectively. The RIA established in this study provides a useful tool to investigate the pathophysiological significance of alpha-ANP and related peptides in cardiovascular disorders and shows that gamma-ANP is not only a precursor of alpha-ANP but acts as an important hormone.

Amino Acid Sequence↗
PubMed1984

Human leumorphin is a potent, kappa opioid receptor agonist.

The opioid activity and opioid receptor type specificity of synthetic human leumorphin were studied in vitro. Human leumorphin inhibited the contraction of the myenteric plexus-longitudinal muscle preparation of the guinea pig ileum and was similar in opioid potency to porcine leumorphin. This action of human leumorphin was antagonized less effectively by naloxone than by the opiate antagonist Mr 2266. Human leumorphin also inhibited the contraction of the rabbit vas deferens which has only the kappa-type opioid receptor. It is concluded that human leumorphin has potent opioid activity and acts as an agonist at the kappa-type opioid receptor, like porcine leumorphin and other peptides derived from preproenkephalin B.

Animals↗
PubMed1984

Leumorphin is a novel endogenous opioid peptide in man.

Porcine leumorphin, a putative opioid peptide corresponding to amino acid residues 228-256 of preproenkephalin B has been demonstrated to exist in the porcine neurointermediate pituitary. A recent study on the sequence analysis of genomic DNA of human preproenkephalin B has shown that human leumorphin differs in 3 amino acid residues from porcine leumorphin. In order to clarify whether leumorphin is an endogenous opioid peptide in man, we have studied its existence in the human brain using a radioimmunoassay and its opioid activity by a bioassay with the guinea-pig ileum myenteric plexus-longitudinal muscle preparation. High performance gel permeation chromatography and reverse-phase high performance liquid chromatography coupled with the radioimmunoassay for leumorphin have revealed that human leumorphin exists in water extracts of the human striatum. In the guinea-pig ileum assay, synthetic human leumorphin exhibited potent opioid activity, with the concentration of 3nM to give 50 per cent inhibition. These results indicate that leumorphin is a novel endogenous opioid peptide in man.

Adult↗
PubMed1984

Demonstration and characterization of immunoreactive methionine-enkephalin, leucine-enkephalin, methionine-enkephalin-Arg6-Gly7-Leu8 and methionine-enkephalin-Arg6-Phe7 in human phaeochromocytoma.

To elucidate whether or not human phaeochromocytoma contains methionine-enkephalin-Arg6-Gly7-Leu8 (Met-enkephalin-Arg-Gly-Leu) and methionine-enkephalin-Arg6-Phe7 (Met-enkephalin-Arg-Phe) together with methionine-enkephalin (Met-enkephalin) and leucine-enkephalin (Leu-enkephalin), all of which are known to exist in the same precursor molecule (preproenkephalin A), we examined extracts from 16 phaeochromocytomas using high performance liquid chromatography (HPLC) and gel exclusion chromatography coupled with radioimmunoassays (RIAs) for these four opioid peptides. Met-enkephalin-Arg-Gly-Leu-like immunoreactivity (-LI) and Met-enkephalin-Arg-Phe-LI existed together with Met-enkephalin-LI and Leu-enkephalin-LI in 16 phaeochromocytomas. There was a wide variation in contents of Met-enkephalin-LI, Leu-enkephalin-LI, Met-enkephalin-Arg-Gly-Leu-LI and Met-enkephalin-Arg-Phe-LI. Significant positive correlations were observed among the contents of these four opioid peptides in 16 phaeochromocytomas. HPLC and gel exclusion chromatography followed by the RIAs showed the presence of Met-enkephalin, Leu-enkephalin, Met-enkephalin-Arg-Gly-Leu and Met-enkephalin-Arg-Phe together with their high molecular weight forms, which existed in variable amounts. Molar ratios of the contents of these four opioid peptides determined after HPLC varies from case to case. These results indicate the co-existence of Met-enkephalin, Leu-enkephalin, Met-enkephalin-Arg-Gly-Leu and Met-enkephalin-Arg-Phe in human phaeochromocytomas, suggesting the preservation of amino acid sequences of these four opioid peptides even in neoplastic tissues.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1983

Leumorphin is a novel endogenous opioid peptide derived from preproenkephalin B.

Using synthetic leumorphin, we obtained antisera for leumorphin and set up two radioimmunoassays (RIAs) with different specificities. Gel exclusion chromatography coupled with the two RIAs showed the existence of a considerable amount of leumorphin-like peptide in water extracts from porcine neuro-intermediate pituitaries. Reverse phase high performance liquid chromatography revealed that leumorphin-like peptide in the water extracts was indistinguishable from synthetic leumorphin. These results along with potent opioid activity of leumorphin indicate that leumorphin is a novel endogenous opioid peptide derived from preproenkephalin B.

Animals↗