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Biomedical subjects

E Ekblad

Publications and source records attributed to E Ekblad.

At least 91 records · Page 5Linked to original sources
PubMed1987

Immunoreactive delta sleep-inducing peptide in pituitary adrenocorticotropin/alpha-melanotropin cells and adrenal medullary cells of the pig.

Immunoreactive delta sleep-inducing peptide (DSIP) is known to occur in the central nervous system and in body fluids including cerebrospinal fluid, blood and urine. However, the exact nature of the immunoreactive material demonstrated has been a matter of discussion. In the present study, DSIP-like immunoreactivity was demonstrated in the porcine pituitary and adrenal medulla using radioimmunoassay and immunocytochemistry. In the pituitary, the DSIP-like material was present in a subpopulation of the cells storing adrenocorticotropin and alpha-melanotropin. The DSIP immunoreactive cells in the adrenal medulla were identical with a major population of the noradrenaline-storing cells. High-performance liquid chromatography of tissue extracts revealed one major peak of DSIP-like immunoreactivity which did not coelute with synthetic DSIP. The immunoreactive material may represent N-terminally truncated fragments of DSIP. The present results suggest that the anterior and intermediate lobes of the pituitary and the adrenal medulla are potential sources of DSIP-like peptides.

Adrenal Medulla↗
PubMed1986

Histamine in endocrine cells in the stomach. A survey of several species using a panel of histamine antibodies.

Antibodies to histamine were used to examine the localization of the amine in cells of the stomach and upper small intestine of a great variety of species, including cartilaginous and bony fish, amphibia, reptiles (lizard), birds (chicken) and a large number of mammals. In all species gastric histamine was localized in endocrine cells (invariably found in the epithelium) and mast cells (usually with an extra-epithelial localization). The endocrine cells were identified as such by immunostaining with antibodies to chromogranin A and the mast cells were identified by toluidine blue staining. Histamine-immunoreactive endocrine cells were found almost exclusively in the acid-producing part of the stomach; only rarely were such cells observed in the pyloric gland area. They were fairly numerous in the gastric mucosa of the two subclasses of fish as well as in the amphibia and reptile species studied. Here, the majority of the histamine-immunoreactive endocrine cells seemed to have contact with the gastric lumen (open type cells) and were located in the surface epithelium (certain fish only) or together with mucous neck cells at the bottom of the pits. In the chicken, histamine-immunoreactive endocrine cells were numerous and located peripherally in the deep compound glands. They were without contact with the lumen (closed type) and had long basal extensions ("paracrine" appearance), running close to the base of the oxyntic-peptic cells. In mammals, the number of histamine-immunoreactive endocrine cells in the stomach varied greatly. They were particularly numerous in the rat and notably few in the dog, monkey and man. In all mammals, the histamine-immunoreactive endocrine cells were of the closed type and located basally in the oxyntic glands. They often had a "paracrine" appearance with long basal processes. Histamine-storing mast cells, finally, were few in both subclasses of fish as well as in the amphibian species and in the lizard. They were fairly numerous in chicken proventriculus (beneath the surface epithelium), few in the oxyntic mucosa of mouse, rat and hamster, moderate in number in hedgehog, guinea-pig, rabbit, pig and monkey, and numerous in cat, dog and man.(ABSTRACT TRUNCATED AT 400 WORDS)

APUD Cells↗
PubMed1986

Existence and coexistence of peptides in nerves of the mammalian ovary and oviduct demonstrated by immunocytochemistry.

The immunocytochemical distribution of substance P (SP), gastrin releasing peptide (GRP), vasoactive intestinal polypeptide (VIP), peptide histidine isoleucine (PHI), and neuropeptide Y (NPY) was studied in the ovary and the Fallopian tube (oviduct) of rats, guinea-pigs, cows, pigs and humans. Generally, the nerve supply was better developed in the oviduct than in the ovary. GRP fibers were most scarce in all tissues. Nerves containing SP were particularly numerous in the oviduct of rat and guinea-pig, supplying the muscular wall and blood vessels. VIP and PHI coexisted in dense plexuses of nerves, not only around blood vessels but also in the follicular wall and the interstitial gland of the ovary, as well as within the smooth muscle layers and subepithelially in the oviduct. The general distribution of NPY was similar, but these immunoreactive nerves were even more numerous. Sequential staining for dopamine-beta-hydroxylase and NPY together with results of chemical sympathectomy with 6-hydroxydopamine suggested that NPY was stored in the noradrenergic sympathetic nerves.

Animals↗
PubMed1986

Neuronal localization and motor effects of gastrin-releasing peptide (GRP) in rat uterus.

All parts of the internal female reproductive tract of the rat contained nerve fibers with immunocytochemically visible gastrin-releasing peptide (GRP)-like material. GRP-like immunoreactivity was also seen in nerve cell bodies of the paracervical ganglion formation, which in addition, harboured GRP nerve fibers. Pharmacological experiments were performed on isolated uterine and cervical smooth muscle tissue from two groups of spayed animals, one of which received estradiol. Both GRP and its non-mammalian counterpart, bombesin, evoked concentration-dependent clonic contractions in uterus and cervix, most pronounced in the estrogen-treated animals. Bombesin induced a stronger contractile force than GRP. The responses were not affected by tetrodotoxin. The observations suggest that GRP may be one of several neural messengers involved in the control of uterine motor activity.

Animals↗
PubMed1986

Calcitonin gene-related peptide (CGRP): perivascular distribution and vasodilatory effects.

The distribution of perivascular nerve fibers displaying calcitonin gene-related peptide (CGRP) immunoreactivity and the effect of CGRP on vascular smooth muscle were studied in the guinea-pig. Perivascular CGRP fibers were seen in all vascular beds. Generally, they were more numerous around arteries than veins. Small arteries in the respiratory tract, gastrointestinal tract and genitourinary tract had numerous CGRP fibers. The gastroepiploic artery in particular received a rich supply of such fibers. Coronary blood vessels had a moderate supply of CGRP fibers. In the heart, a moderate number of CGRP fibers was seen running close to myocardial fibers. The atria had a richer supply than the ventricles. Numerous CGRP immunoreactive nerve cell bodies and nerve fibers were seen in sensory (trigeminal, jugular and spinal dorsal root) ganglia. Sequential or double immunostaining with antibodies against substance P and CGRP suggested co-existence of the two peptides in nerve cell bodies in the ganglia and in perivascular fibers. In agreement with previous findings CGRP turned out to be a strong vasodilator in vitro as tested on several blood vessels (e.g. basilar, gastroepiploic and mesenteric arteries). Conceivably, perivascular CGRP/SP fibers have a dual role as regulator of local blood flow and as carrier of sensory information.

Animals↗
PubMed1985

Origin and distribution of neuropeptide Y-, vasoactive intestinal polypeptide-and substance P-containing nerve fibers in the urinary bladder of the rat.

The origin and distribution in the urinary bladder of nerve fibers containing neuropeptide Y (NPY), vasoactive intestinal polypeptide (VIP) and substance P (SP) were investigated in rats. Experimental procedures comprised preganglionic decentralization or postganglionic denervation of the bladder and also chemical sympathectomy as well as capsaicin treatment of newborn rats. Nerve fibers containing NPY were richly distributed in the detrusor muscle and also in the pelvic ganglia. Numerous NPY-containing nerve cell bodies were found in pelvic ganglia. A rich occurrence of VIP fibers and a more sparse distribution of SP-containing fibers were also found in the bladder as well as a relatively rich representation of VIP-containing nerve cell bodies in the pelvic ganglia. After decentralization the intensity of VIP and NPY immunofluorescence increased in nerve cell bodies of the pelvic ganglia and in nerve fibers in the wall of the bladder. Postganglionic denervation, on the other hand, eliminated all peptides examined in the bladder wall. After postganglionic denervation the situation in the ganglia was approximately the same as after decentralization. Chemical sympathectomy (6-OHDA) did not seem to change significantly the frequency and distribution of VIP-, SP- and NPY-fibers in the muscle layer of the bladder or in the pelvic ganglia, while the NPY-containing nerve fibers in the submucosal layer and around blood vessels of the bladder disappeared. Adrenergic nerve fibers in the wall of the bladder (visualized by histofluorescence) were markedly reduced in number after administration of 6-OHDA.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1985

Peptide-containing nerve fibers in the stomach wall of rat and mouse.

Peptide-containing nerve fibers were found to be numerous in the glandular stomach of the rat and mouse. The immunoreactive neuropeptides demonstrated included vasoactive intestinal polypeptide (VIP), peptide histidine isoleucine (PHI), gastrin-releasing peptide (GRP), substance P (SP), enkephalin, somatostatin, cholecystokinin, and neuropeptide Y (NPY). The density and distribution of the various peptide-containing fibers did not differ overtly between the pyloric and oxyntic gland areas except for the GRP fibers, which were fewer in the pyloric than in the oxyntic mucosa. The entire VIP nerve fiber population was found to also contain PHI. Immunoreactive NPY was found to occur in the VIP/PHI fibers (VIP/PHI/NPY fibers) in the smooth muscle and intramural ganglia of both rat and mouse and in the mucosa of the mouse. Mucosal VIP/PHI fibers in the rat did not contain any NPY-like material. Perivascular NPY fibers in both species and mucosal NPY fibers in the rat did not contain VIP or PHI. The mucosa harbored numerous GRP fibers and VIP/PHI (rat) or VIP/PHI/NPY (mouse) fibers, and a modest number of NPY (rat) and SP fibers. In the submucosa the peptide-containing nerve fibers were found mainly in the ganglia and around blood vessels. Blood vessels received a rich supply of NPY fibers; the number of perivascular VIP/PHI, GRP, and SP fibers was much lower by comparison. The smooth muscle and myenteric ganglia harbored not only VIP/PHI/NPY, GRP, and SP fibers but also enkephalin, somatostatin, and cholecystokinin fibers. Gastrin-releasing peptide, VIP/PHI/NPY, SP, and enkephalin nerve cell bodies occurred in the myenteric ganglia. As studied in the rat, vagal denervation did not affect the density and distribution of the various peptide-containing nerve fibers. After sympathectomy, mucosal and perivascular NPY fibers disappeared. The other types of peptide-containing nerve fibers were not affected.

Animals↗
PubMed1985

Neuropeptide Y-like immunoreactivity in perivascular nerve fibres of the guinea-pig.

The distribution of perivascular nerve fibres displaying neuropeptide Y-like immunoreactivity was studied in the guinea-pig. Generally, neuropeptide Y fibres were numerous around arteries and moderate in number around veins. In the heart, immunoreactive fibres were numerous in the auricles and the atria (epi- and endocardium) whereas the ventricles had a more scarce supply. The coronary vessels were richly supplied with fibres. Around large elastic and muscular arteries the fibres formed well developed plexuses. Small arteries in the respiratory tract, the gastrointestinal tract and the genito-urinary tract received a particularly rich supply. In the liver, spleen and kidney only few perivascular fibres were seen. Since immunoreactive fibres around blood vessels disappeared upon surgical or chemical sympathectomy, and sequential immunostaining with antisera against dopamine-beta-hydroxylase (a marker for adrenergic neurons) and against neuropeptide Y revealed their co-existence, it is concluded that neuropeptide Y fibres around blood vessels are sympathetic and adrenergic.

Animals↗
PubMed1985

Two distinct VIP precursors in cartilaginous fish?

In the ray gut immunoreactive VIP has a dual localization in endocrine cells and in nerve fibers. Immunoreactive VIP and PHI were found to co-exist in the same nerve fibers. This is predictable, since VIP and PHI derive from the same precursor. However, PHI could not be demonstrated in the VIP immunoreactive endocrine cells. Chromatographic analysis (high performance liquid chromatography) of extracts of the gut revealed two different molecular forms of VIP, one large peak with an elution position similar to that of authentic porcine VIP and a minor peak with a different elution position. The results suggest either the existence of different precursors for VIP in endocrine cells and in neurons, or the different processing of the same precursor in neurons and endocrine cells.

Animals↗
PubMed1985

Galanin nerve fibers in the rat gut: distribution, origin and projections.

Galanin, a 29 amino acid peptide, was recently isolated from the porcine gut. Immunocytochemistry revealed a dense network of galanin-immunoreactive nerve fibers in the submucosa, smooth muscle layers and intramural ganglia throughout the rat gastrointestinal tract. In the smooth muscle the density of innervation was lower in the colon than in the small intestine. In the mucosa galanin-immunoreactive fibers were quite numerous in the small intestine, less numerous in the large intestine and rare in the stomach. A moderate number of galanin-immunoreactive nerve cell bodies could be detected in the myenteric ganglia throughout the digestive tract and in the submucous ganglia of the intestines. Enteric galanin-immunoreactive fibers seem to be intrinsic to the gastrointestinal tract since their distribution and frequency were unaffected after extrinsic denervation (chemical sympathectomy, vagal denervation or clamping of nerves running within the mesenterium). Myectomy at the mid-jejunal level resulted in a total loss of galanin-immunoreactive nerve fibers 5 mm anally to the lesion with a gradual return of galanin-immunoreactive fibers up to 15-20 mm further anally; there was no overt loss of fibers orally. The findings indicate that myenteric galanin-immunoreactive neurones issue long descending projections that terminate either within the myenteric ganglia or in the smooth muscle.

Animals↗
PubMed1985

Galanin: neuromodulatory and direct contractile effects on smooth muscle preparations.

The effects of galanin, a newly isolated neuropeptide, and of a galanin fragment (galanin 1-10) were studied on various smooth muscle preparations in vitro. Direct motor effects as well as effects on electrically induced (neuronally mediated) responses (neuromodulatory effects) were observed. Both gatanin and galanin 1-10 evoked a strong contractile response in rat jejunal longitudinal muscle. This effect was a direct one on the smooth muscle. Addition of galanin to guinea-pig taenia coli inhibited the contractile response to electrical stimulation, mediated by endogenous substance P and acetylcholine. In the rabbit iris sphincter, galanin reduced the acetylcholine-mediated but not the substance P-mediated contraction evoked by electrical stimulation. The neuromodulatory effects seem to be presynaptic and require the whole or possibly only the C-terminal part of the galanin molecule, since galanin 1-10 was ineffective. Rabbit femoral artery and vein, gastroepiploic and basilar arteries and guinea-pig trachea and main bronchi did not respond to either galanin or galanin 1-10.

Animals↗
PubMed1985

Neuropeptide Y potentiates noradrenaline-evoked vasoconstriction: mode of action.

Neuropeptide Y (NPY), which co-exists with noradrenaline (NA) in postganglionic sympathetic nerves, was able to potentiate NA-evoked constriction in certain isolated rabbit blood vessels. The phenomenon was observed in the femoral, the gastroepiploic and the pulmonary arteries but not in the femoral or the gastroepiploic veins or in the aorta. Thus, NPY potentiated NA-evoked vasoconstriction predominantly in muscular arteries with alpha-1 adrenoceptors. NPY-related peptides, such as peptide YY and to some extent pancreatic polypeptide shared this ability, whereas calcitonin gene-related peptide or LPLRFamide did not. The mode of action by which NPY potentiates NA-evoked vasoconstriction was analyzed using the femoral artery. Pretreatment of the vessel with cocaine, a blocker of amine re-uptake, or rolipram, an inhibitor of phosphodiesterase, left the potentiation unaffected, whereas Na+ deficiency or ouabain, an inhibitor of Na+/K+-adenosine triphosphatase, abolished this effect of NPY. Nifedipine, a blocker of Ca++ entry, or removal of extracellular Ca++ shortly before the application of NPY had little effect. After prolonged exposure to a Ca++-free medium (with ethylene glycol bis(beta-aminoethyl ether)-N,N'-tetraacetic acid) the maximum response to NA was greatly reduced and the potentiating effect of NPY was abolished. Thus, the potentiation of NA-evoked vasoconstriction by NPY seems to depend upon the presence of Na+ but not upon a Ca++ influx. An intracellular sequestered Ca++ pool appears to play a critical role.

Animals↗
PubMed1984

Coexistence of peptide YY and glicentin immunoreactivity in endocrine cells of the gut.

Endocrine cells containing peptide YY (PYY) were numerous in the rectum, colon and ileum and few in the duodenum and jejunum of rat, pig and man. No immunoreactive cells could be detected in the pancreas and stomach. Coexistence of PYY and glicentin was revealed by sequential staining of the same section and by staining consecutive semi-thin sections. Since the PYY sequence is not contained in the glucagon/glicentin precursor molecule the results suggest that the PYY cell in the gut expresses two different genes coding for regulatory peptides of two different families.

Animals↗
PubMed1984

VIP and PHI coexist with an NPY-like peptide in intramural neurones of the small intestine.

Vasoactive intestinal peptide (VIP), peptide histidine isoleucine (PHI) and neuropeptide Y (NPY) are neuropeptides present in all layers of the small intestine. NPY-immunoreactive fibres in the gut seem to derive from two sources. One population is of extramural (sympathetic) origin and contains noradrenaline, another is of intramural origin and does not contain noradrenaline. In the present study of mouse, rat and pig, immunocytochemistry showed immunoreactive PHI to coexist completely with immunoreactive VIP. This was predictable, since VIP and PHI derive from the same precursor. In addition, however, VIP and PHI were found to coexist with immunoreactive NPY in non-adrenergic (but not in adrenergic) nerve fibres and nerve cell bodies. This coexistence was unexpected, since the VIP precursor does not contain NPY-like sequences.

Animals↗