Biomedical subjects

V Mutt

Publications and source records attributed to V Mutt.

At least 91 records · Page 5Linked to original sources

PubMed1985

Neuropeptide K: isolation, structure and biological activities of a novel brain tachykinin.

A 36 amino acid residue peptide, which contains a substance K sequence at its C-terminus has been isolated from porcine brain extracts. The primary structure of the peptide, designated neuropeptide K (NPK), was found to be: (sequence; see text) This N-terminally extended form of substance K is present in a high concentration in the brain. The peptide is highly biologically active with regard to gallbladder contraction, protein extravasation, hypotension and bronchial smooth muscle spasm and may act as an additional tachykinin neuromessenger.

Amino Acid Sequence↗

PubMed1985

Isolation and characterization of neuropeptide Y from porcine intestine.

The isolation and primary structure of intestinal neuropeptide Y (NPY) is described. The peptide was purified from porcine intestinal extracts using a chemical assay and radioimmunoassay for NPY. The amino acid sequence of this peptide is: Tyr-Pro-Ser-Lys-Pro-Asp-Asn-Pro-Gly-Glu-Asp-Ala-Pro-Ala-Glu-Asp-Leu-Ala- Arg-Tyr-Tyr- Ser-Ala-Leu-Arg-His-Tyr-Ile-Asn-Leu-Ile-Thr-Arg-Gln-Arg-Tyr-NH2. This the structure of intestinal NPY is identical to the NPY of brain origin.

Amino Acid Sequence↗

PubMed1985

Distribution of galanin-like immunoreactivity in the gastro-intestinal tract of several mammalian species.

The distribution of galanin-immunoreactive (GAL-IR) neurons was mapped in detail in the gastro-intestinal tract of the rat, mouse, guinea-pig and pig by use of the indirect immunofluorescence technique. GAL-IR cell bodies were found in both the submucous and the myenteric plexus, with considerably higher numbers in the former ganglia. The largest number of GAL-IR perikarya was seen in the duodenal submucous plexus of the pig. With some (single) exceptions, GAL-IR cell somata were not observed in the myenteric plexus of the pig and guinea-pig, and in the submucous plexus of the esophagus and the stomach of the guinea-pig. GAL-IR fibers occurred in most parts of the gastro-intestinal tract. In the lamina propria a few non-varicose, weakly fluorescent fibers were noted in the mouse and rat, whereas in the pig and guinea-pig were large numbers of GAL-IR fibers with a varicose appearance was observed. These fibers were in all species most numerous in the distal portion of the intestinal tract. In the submucosa GAL-IR fibers were detected in all four species, and in the pig and guinea-pig some fibers surrounded blood vessels. A large number of GAL-IR fibers was generally seen in the circular smooth muscle layer, except in the guinea-pig, which only seemed to contain a few fibers. In the longitudinal muscle layer only single fibers could be detected. However, the gastric fundus region of the pig contained a moderate number of fibers in the longitudinally and obliquely oriented layers. In general, in the rat, mouse and pig, the submucous and myenteric plexus contained moderate or large numbers of GAL-IR fibers. In the guinea-pig, no or only single fibers were observed in the plexus of the upper gastro-intestinal tract and the rectum, while moderate numbers were seen in the ileum and colon. Thin adjacent sections stained for vasoactive intestinal polypeptide (VIP) and GAL revealed the coexistence of these two peptides in cell bodies of the myenteric plexus in the pig duodenum and guinea-pig colon. In these two species the GAL- and VIP-nerve fiber networks also exhibited marked similarities. However, in the rat and mouse VIP- and GAL-distribution patterns were in general different. The present findings indicate the presence of yet another neuropeptide or peptide family in the gastro-intestinal tract of several rodents and the pig.

Animals↗

PubMed1985

Cardiodilatin-immunoreactive neurons in the hypothalamus of Tupaia.

Using various region specific antibodies raised against partial sequences of synthetic cardiodilatin (CDD) we detected immunoreactive neurons with their perikarya in the nucleus periventricularis of Tupaia belangeri. The fibers could be traced laterally directed towards the amygdaloid complex and some varicosities were also observed in the lateral parts of the nucleus periventricularis. It is postulated that brain CDD represents a new neuropeptide and that these CDD-IR neurons are involved in specific functions related to the modulation of the cardiovascular centers.

Animals↗

PubMed1985

Characterization of two novel forms of cholecystokinin isolated from bovine upper intestine.

The primary structures of two novel forms of cholecystokinin, isolated from bovine upper intestine are reported. The two peptides are composed of 33 and 39 amino acid residues, respectively, the larger being an N-terminally extended form of the shorter peptide. The primary structure of the 39 amino acid peptide is: (Formula: see text) This amino acid sequence differs from the porcine hormone at positions 13 and 15, which are Val and Met, respectively, in pig, the same amino acid substitutions have previously been found to occur also in dog.

Amino Acid Sequence↗

PubMed1985

Comparative effects of vasoactive intestinal peptide and secretin on exocrine pancreatic secretion in the cat.

The stimulatory effect of vasoactive intestinal peptide (VIP) and secretin has been compared on exocrine pancreatic secretion in anaesthetized cats. Both peptides were given by bolus intravenous injection and continuous intravenous infusion. After bolus injection, VIP stimulated pancreatic secretion only weakly. On the contrary, during intravenous infusion, the maximal effect of VIP did not differ significantly from that of secretin. Therefore, while the potency of VIP is always lower than that of secretin, its efficacy appears to be strictly dependent on the mode of administration.

Animals↗

PubMed1985

Galanin inhibits insulin secretion and induces hyperglycemia in dogs.

Intravenous administration of galanin into fasted conscious dogs produced a dose-dependent hyperglycemia accompanied by decreases in plasma insulin levels, but with no elevation of plasma glucagon levels. Galanin infusions produced greater parenteral glucose-induced rises in plasma glucose levels along with markedly blunted insulin responses compared with glucose and insulin responses to control glucose infusions. Immediately after cessation of the galanin infusions, elevation of plasma insulin levels occurred in the basal state and after parenteral glucose loading. These results suggest that galanin's hyperglycemic activity is predominantly mediated by a reversible inhibition of insulin secretion.

Amino Acid Sequence↗

PubMed1984

Neuropeptide Y receptor in the rat brain.

The specific binding of the chloramine-T iodinated neuropeptide Y (125I-NPY) to membranes from rat cerebral cortex was investigated using equilibrium binding and kinetic methods. The equilibrium binding of 125I-NPY at 37 degrees C was characterized by a Kd value of 0.38 nM. The receptor densities in the cerebral cortex, hypothalamus and cerebellum were 0.45 pmol/mg, 0.47 pmol/mg and 0.04 pmol/mg protein respectively. The binding site for 125I-NPY was sensitive to treatment with proteolytic enzymes and thiol reagents. The binding showed a sharp optimum at pH 7-7.7 and was inhibited by increasing concentrations of Mg2+.

Animals↗

PubMed1984

A novel form of gastric inhibitory polypeptide (GIP) isolated from bovine intestine using a radioreceptor assay. Fragmentation with staphylococcal protease results in GIP1-3 and GIP4-42, fragmentation with enterokinase in GIP1-16 and GIP17-42.

A novel form of gastric inhibitory polypeptide (GIP), later also referred to as glucose-dependent insulinotropic polypeptide, has been isolated from bovine upper intestine. The purification was monitored by a recently developed radioreceptor assay, specific for GIP, using membrane preparations from hamster beta-cell tumors. A combination of ion-exchange and reverse-phase high-performance liquid chromatography was used in the isolation which resulted in homogeneous bovine GIP. Bovine GIP is, like porcine GIP, composed of 42 amino acid residues. The sequence is: Tyr-Ala-Glu-Gly-Thr-Phe-Ile-Ser-Asp-Tyr-Ser-Ile-Ala-Met-Asp-Lys-Ile-Arg- Gln-Gln - Asp-Phe-Val-Asn-Trp-Leu-Leu-Ala-Gln-Lys-Gly-Lys-Lys-Ser-Asp-Trp-Ile-His- Asn-Ile - Thr-Gln, which differs from that of the previously characterized porcine GIP by having isoleucine instead of lysine at position 37. Upon proteolytic digestion of GIP with the staphylococcal V8 protease and with enterokinase, two fragments are formed in each case, corresponding to GIP1-3, GIP4-42, and GIP1-16, GIP17-42, respectively.

Amino Acid Sequence↗

PubMed1984

A novel form of the polypeptide PHI isolated in high yield from bovine upper intestine. Relationships to other peptides of the glucagon-secretin family.

A novel form of the polypeptide termed PHI (peptide HI with N-terminal histidine and C-terminal isoleucine amide) has been isolated from bovine upper intestine. This bovine peptide was obtained in a 40 times higher yield than the corresponding polypeptide isolated from porcine intestine. Bovine PHI is, like porcine PHI, composed of 27 amino acid residues. The complete amino acid sequence of the bovine peptide is His-Ala-Asp-Gly-Val-Phe-Thr-Ser-Asp-Tyr-Ser-Arg-Leu-Leu-Gly-Gln-Leu-Ser- Ala- Lys-Lys-Tyr-Leu-Glu-Ser-Leu-Ile-NH2. This sequence differs from porcine PHI at position 10 and from human PHI at positions 10, 12 and 27. The amino acid residue exchange between porcine and bovine PHI makes the latter more similar to the vasoactive intestinal polypeptide (VIP), gastric inhibitory polypeptide (GIP), glucagon and the growth-hormone-releasing factor (GRF).

Amino Acid Sequence↗

PubMed1984

Isolation and primary structure of human PHI (peptide HI).

The isolation of the human form of PHI (peptide HI) is described. The peptide was purified from human colonic extracts by using a chemical method for the detection of its C-terminal amidated structure. Human PHI consists of 27 amino acid residues and the complete amino acid sequence is: His-Ala-Asp-Gly-Val-Phe-Thr-Ser-Asp-Phe-Ser-Lys-Leu-Leu-Gly-Gln-Leu-Ser- Ala-Lys-Lys-Tyr-Leu-Glu-Ser-Leu-Met-NH2. The differences between the structures of porcine and human PHI are at position 12 (Arg/Lys replacement) and at position 27 (Ile/Met).

Amino Acid Sequence↗

PubMed1984

Isolation and characterization of cholecystokinin-58 (CCK-58) from porcine brain.

A 58-residue peptide has been isolated from extracts of porcine brain and shown to be an N-terminally extended cholecystokinin (CCK). The amino acid sequence of this peptide is: Ala-Val-Gln-Lys-Val-Asp-Gly-Glu-Ser-Arg-Ala-His-Leu-Gly-Ala-Leu-Leu-Ala- Arg-Tyr- Ile-Gln-Gln-Ala-Arg-Lys-Ala-Pro-Ser-Gly-Arg-Val-Ser-Met-Ile-Lys-Asn-Leu- Gln-Ser- Leu-Asp-Pro-Ser-His-Arg-Ile-Ser-Asp-Arg-Asp-Tyr(SO3)-Met-Gly-Trp-Met-Asp -Phe-NH2. The peptide was found to induce contraction of the guinea-pig gallbladder, but the pattern of this action seemed to differ from those of CCK-8 and CCK-33.

Amino Acid Sequence↗

PubMed1984

A galanin-like peptide in the central nervous system and intestine of the rat.

Galanin (GAL), a 29 amino acid peptide, was recently isolated from the small intestine of pigs. In the present study an antiserum towards porcine GAL has been developed and used for radioimmunoassay and immunohistochemical studies. We now report that GAL-like immunoreactivity occurs in wide-spread systems in the rat CNS and intestine.

Animals↗

PubMed1984

A C-terminal fragment of hemoglobin beta-chains in extracts of porcine upper intestine.

A 32-residue peptide has been isolated from extracts of porcine upper intestine. Amino acid sequence determination showed that the peptide is a fragment of hemoglobin, corresponding to the C-terminal part of the beta-chain. The region in the beta-chain which precedes the isolated fragment is hydrophobic (8 Leu/Val/Ile) and has no charges at 10 preceding positions. It therefore, to some extent, resembles the structure of 'signal sequences' which may suggest a specific cleavage site in hemoglobin beta-chains.

Amino Acid Sequence↗

PubMed1984

Immunohistochemical localization of cardiodilatin in myoendocrine cells of the cardiac atria.

Region-specific antibodies against synthetic N-terminal fragments of cardiodilatin (CDD) were raised in rabbits and used for the immunohistochemical detection of this new peptide hormone in the myoendocrine cells within the cardiac atria of several species. The peroxidase-antiperoxidase (PAP) and fluorescein isothiocyanate (FITC) immunohistochemical methods gave identical results of cardiodilatin-immunoreactivity (CDD-IR) within the tissue. In addition to the porcine right atrial appendage, myoendocrine cells with CDD-IR were also detected in the left atrium of porcine heart, as well as in other species such as dog and cat. The exact localization of the immunoreactivity in specific secretory granules was mostly related to the Golgi-area which is located on both nuclear poles of auricular myoendocrine cells. The results confirm that cardiodilatin is stored in secretory granules observed through electron microscopical means. This hormone is most likely synthesized and released in myoendocrine cells, exerting its important cardiovascular effects.

Animals↗

PubMed1984

Secretin, VIP, and PHI stimulate rat proximal duodenal surface epithelial bicarbonate secretion in vivo.

The surface epithelial cells of the stomach and duodenum secrete bicarbonate at rest and in response to a number of agonists including the gastrointestinal hormones, glucagon, and GIP. Since those hormones with structural homology may have similar effects, the purpose of the present study was to examine the effect of graded doses (6, 24, and 96 nmol/kg) of pure porcine secretin, VIP, and PHI on bicarbonate secretion by the proximal duodenum containing Brunner's glands. Experiments were performed in vivo on unanesthetized Sprague-Dawley rats with chronic Thiry-Vella type loops of the proximal 2 cm of duodenum. The order of testing was random and only one hormone was tested on a single day. Compared to the saline control, each dose of VIP produced a significant increase in duodenal bicarbonate secretion in a dose-response manner. The two higher doses of secretin and only the 96 nmol/kg dose of PHI significantly increased bicarbonate output. The responses to 96 nmol/kg dose of secretin and VIP were similar, and each was significantly greater than observed with PHI. It is concluded that secretin and VIP stimulate proximal duodenal bicarbonate secretion and are more potent than PHI.

Animals↗

PubMed1984

Differential co-existence of neuropeptide Y (NPY)-like immunoreactivity with catecholamines in the central nervous system of the rat.

The distribution of neuropeptide Y immunoreactive cell bodies in relation to various types of catecholamine-containing cell bodies in the rat brain was analyzed immunohistochemically using antisera to tyrosine hydroxylase, dopamine beta-hydroxylase and phenylethanolamine N-methyltransferase. Coexistence of the peptide in catecholamine cell bodies was established by using an elution-restaining procedure. Neuropeptide Y-like immunoreactivity was observed in most noradrenergic cell bodies of the Al/Cl cell groups in the ventro lateral medulla oblongata. Similarly this peptide immunoreactivity was also observed in the majority of the adrenergic cell bodies of the C2 group. In the dorsal and dorsal-lateral part of the nucleus of the solitary tract, where a group of small adrenergic cells is present, several small neuropeptide Y immunoreactive cells were also observed. The possibility of coexistence of adrenaline and neuropeptide Y in these cells remains to be established. The majority of the noradrenergic cell bodies of the A2 group, as well as the presumptive dopaminergic cells within its ventromedial part, seemed to lack neuropeptide Y-like immunoreactivity. Many noradrenergic cell bodies of the A6 group in the locus coeruleus proper were neuropeptide Y-immunoreactive, whereas the peptide could not be observed in the subcoeruleus group. Neither the A5 and A7 noradrenergic cells in the pons, nor any of the dopaminergic cell groups in the mesencephalon and forebrain (A8-A15) seemed to contain a neuropeptide Y-like peptide. The findings indicate that central catecholamine neurons can be subdivided into distinct sub-groups based upon the coexistence of a specific peptide.

Animals↗

PubMed1984

Actions of centrally administered neuropeptide Y on EEG activity in different rat strains and in different phases of their circadian cycle.

The effects of centrally administered neuropeptide Y (NPY) on the sleep-wakefulness cycle have been studied by analyzing its action in different strains of rats with or without spontaneous hypertension and during two different phases of the circadian cycle. Normal adult Sprague-Dawley (SD), Wistar-Kyoto (WKy) and spontaneous hypertensive (SH) rats were used. By means of EEG electrodes the recording of the fronto-parietal electrocorticogram and the electromyogram could be made. Stainless steel cannula were also implanted into the lateral ventricle. The effects of an intraventricular injection of NPY (1.25 nmol/rat) was compared with the effects of the vehicle (saline) alone. The EEG patterns were classified as desynchronized, mixed or synchronized. In the SD rats NPY produced behavioural signs of sedation and a significant reduction of synchronized EEG activity as well as significant increase of synchronized and mixed EEG activities in comparison with the saline treated rats. In the WKy rats NPY administration produced an increase of synchronized EEG activity during evening sessions. In SH rats NPY produced a significant increase of desynchronized EEG activity and a decrease in mixed EEG activity indicating an awakening effect of the peptide. In view of the NPY innervation of the locus ceruleus, it therefore seems possible that the neuronal and hormonal regulation of the locus ceruleus noradrenaline nerve cells is different in the two strains of rats. It also seems possible that the ability of NPY to increase wakefulness in hypertensive animals is related to abnormal changes in the alpha 2-adrenoreceptors taking place in SH rats.

Animals↗