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F Sundler

Publications and source records attributed to F Sundler.

At least 379 records · Page 21Linked to original sources
PubMed1984

Neuropeptide Y: occurrence and distribution in dental pulps.

Nerve fibers displaying neuropeptide Y (NPY) immunoreactivity were seen in the dental pulp of several mammals, including man. Generally, the NPY fibers were more numerous in the apical part than in the coronal part and were distributed around small blood vessels and as single fibers in the pulpal stroma. Sequential staining with antibodies against the enzyme dopamine-beta-hydroxylase (DBH), a marker for adrenergic neurons, and NPY showed that DBH and NPY were located in the same perivascular nerve fibers. Further, since chemical and surgical sympathectomy caused the disappearance of pulpal NPY fibers, it is conceivable that NPY fibers in the dental pulp are identical with adrenergic ones. There is thus a morphological basis for suggesting that NPY and noradrenaline cooperate in regulating pulpal blood flow.

Adrenergic Fibers↗
PubMed1984

Continuous infusion of somatostatin evokes escape of gastric acid inhibition in the rat.

In rats with chronic gastric fistula, constant infusion of somatostatin failed to maintain a sustained inhibition of basal and pentagastrin-stimulated gastric acid secretion for greater than 4-6 h. After 8-12 h, the secretion was back to the level observed before infusion of somatostatin. The desensitization seemed specific in that infusion of secretin at this stage inhibited the secretion. After interruption of an 18-h-infusion, the responsiveness to somatostatin returned gradually; it was completely restored at 2 h. In marked contrast, intermittent administration of somatostatin produced a sustained pulsatile response pattern of the pentagastrin-stimulated acid secretion over a period of 18 h, the rhythm selected being 20 min of somatostatin + pentagastrin infusion followed by 40 min of pentagastrin alone. The desensitization to somatostatin is of particular interest in view of the postulated paracrine nature of the somatostatin cells in the stomach.

Animals↗
PubMed1984

Neuropeptide Y immunoreactive neurons in the guinea-pig uvea and retina.

Neuropeptide Y (NPY) is a recently discovered, amidated 36 amino acid residue neuropeptide present in many but not all sympathetic noradrenergic neurons. In the guinea-pig eye, NPY immunoreactive fibers were found to have the same distribution as noradrenergic fibers except that there were fewer at the iris dilator, in the cornea, and in the chamber angle. In the anterior uvea, the NPY immunoreactive fibers disappeared after excision of the homolateral superior cervical sympathetic ganglion, whereas in the choroid, many NPY immunoreactive fibers remained, indicating that they originate elsewhere. NPY immunoreactivity thus is not found in all sympathetic adrenergic neurons nor is it found only in such nerve fibers. In the retina, NPY immunoreactive fibers formed a single layer of processes in sublamina 1 of the inner plexiform layer. NPY immunoreactive cell bodies were found in the innermost cell row of the inner nuclear layer. The immunoreactivity was concentrated to the hillock region of these cells.

Adrenergic Fibers↗
PubMed1984

Localization of ornithine decarboxylase in mutant CHO cells that overproduce the enzyme. Differences between the intracellular distribution of monospecific ornithine decarboxylase antibodies and radiolabeled alpha-difluoromethylornithine.

The intracellular localization of ornithine decarboxylase (ODC), a key enzyme in polyamine synthesis and cell growth, is a matter of present debate. Using two independent methods of analysis, we have attempted to determine the actual distribution of ODC in a mammalian cell. To overcome the problem of a normally very low cellular ODC content, we have used ODC overproducing mutant CHO cells. These mutant cells exhibit a 10-fold higher ODC activity than do the wild type cells. The localization of ODC protein in exponentially growing cells, was determined by indirect immunofluorescence microscopy (permeabilized whole-cell preparations and 1 micron sections), using a monospecific ODC antibody. The intracellular localization of catalytically active ODC was determined by light and electron microscope autoradiography following pulselabeling of cells with alpha-difluoromethyl(5-3H)ornithine (3H-DFMO) at the time of peak ODC activity. alpha-Difluoromethylornithine (DFMO) is an enzyme-activated irreversible inhibitor of ODC and binds covalently to the active enzyme. The specificity of this reaction in the cell was ascertained by immunoprecipitation of 3H-DFMO-labeled ODC. ODC (as determined by both methods) was present in all the cells of a serum-stimulated monolayer culture. The highest concentration of ODC protein and of catalytically active ODC was observed in the smallest and most rapidly proliferating cells. Polyploid and multinuclear cells always exhibited the lowest concentrations.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1984

Effects of upper abdominal sympathectomy on gastric acid, serum gastrin, and catecholamines in the rat gut.

Selective upper abdominal sympathectomy increased basal acid output in rats but was without effect on stimulated acid output, serum gastrin concentration, and gastric mucosal histidine decarboxylase activity. The sympathectomy was verified by fluorescence histochemistry and determination of tissue catecholamines. A drastic reduction in tissue noradrenaline, adrenaline, and dopamine levels occurred after sympathectomy, and fluorescence microscopy showed a complete loss of adrenergic nerve fibers. Vagotomy reduced catecholamine levels in the stomach wall by 50% but did not affect the catecholamine content in the pancreas and small bowel. Surprisingly, combined vagotomy and upper abdominal sympathectomy resulted in lower catecholamine levels than sympathectomy alone in extragastric but not in gastric tissues.

Animals↗
PubMed1984

The vagus exerts trophic control of the stomach in the rat.

Bilateral subdiaphragmatic truncal vagotomy results in great functional changes in the stomach although the changes in the gastric mucosal architecture are small. A trophic effect of the vagus on the stomach is revealed after unilateral vagal sectioning, taking advantage of the fact that, in the rat, each vagal trunk innervates only one side of the stomach, and that denervation of one side does not impair the functional capacity of the other. The denervated side of the stomach displayed atrophy that was reflected in reduced weight and height of the oxyntic mucosa and a reduced density of argyrophil cells. The lack of atrophy after bilateral vagotomy can be explained by counteracting forces, in that the subsequent rise in gastrin secretion (due to lack of acid feedback inhibition of gastrin release) probably masks antitrophic effects of the vagotomy per se. Interestingly, the number of somatostatin cells in the oxyntic mucosa was not reduced after unilateral vagotomy, nor was the weight of the antral mucosa or the density of enterochromaffin and gastrin cells in the antrum on the denervated side.

Animals↗
PubMed1983

Neuronal histamine in the gut wall releasable by gastrin and cholecystokinin.

Histamine accumulated in the ligated vagus nerve of the rat, both above and below the ligature; maximum accumulation was after 4 h. The finding is suggestive of axonal flow. Further evidence for histamine in peripheral nerves was obtained in experiments showing that the guinea-pig gut wall could be labelled with [3H]histamine. The experiments were carried out with isolated strips of stomach wall and taenia coli. Electrical stimulation released [3H]histamine from these specimens. The release could be blocked by Ca2+-free medium or by tetrodotoxin. The release was unaffected by vagal denervation or chemical sympathectomy (6-hydroxydopamine) but prevented by reserpinization. Gastrin-17 and cholecystokinin-39 released radioactivity by a tetrodotoxin-sensitive mechanism. The possible existence of a gastrin/cholecystokinin-sensitive neuronal pool of histamine in the gut wall offers a new perspective on the postulated role of histamine as a physiological stimulant of gastric acid secretion and might explain why H2-receptor antagonists block gastrin-stimulated acid secretion.

Animals↗
PubMed1983

Neuropeptide Y in the female reproductive tract of the rat. Distribution of nerve fibres and motor effects.

Fluorescence immunocytochemistry revealed the presence of extensive systems of nerve fibres containing neuropeptide Y (NPY) in the rat's ovary, fallopian tube, uterine horns and cervix. The most prominent supply of NPY fibres was found in ther cervix, where they are associated with both vascular and non-vascular smooth musculature. Smooth muscle effect of NPY was studied in an in vitro model using circular cervix preparations from estrogen-treated sprayed rats. NPY onhibited in a dose-dependent way neurally evoked (tetrodotoxin-sensitive) contractions, but had no effect on resting tension. The nerve-induced contractions were blocked by atropine, the experiments thus suggest prejunctional actions of NPY in cholinergic nerves in the uterine cervix.

Animals↗
PubMed1983

Vasoactive intestinal polypeptide (VIP) as a putative neurotransmitter in penile erection.

The localization of vasoactive intestinal polypeptide (VIP) in the male genitourinary tract was investigated in the rabbit and man by means of radioimmunoassay and immunohistochemistry. In addition, the in vitro effect of VIP upon penile smooth muscle from man, the Vervet monkey, and the rabbit was investigated. Significant concentrations of VIP immunoreactivity were found in the human penis and all the organs of the rabbit genital tract apart from the testis. VIP immunoreactive nerve fibres were observed in the erectile tissue of the human and rabbit penis and in the other organs of the rabbit genital tract apart from the testis. Fibres were most abundant in association with blood vessels, in smooth muscle tissue, and subepithelially in glandular tissue. Strips of smooth muscle taken from the corpus cavernosum of Vervet monkey and man showed a dose-dependent relaxation in response to VIP at concentrations of 6 X 10(-8) mol X L-1 and 6 X 10(-7) mol X L-1. The data indicate that VIP may be an inhibitory neurotransmitter involved in the nervous control of penile erection.

Adult↗
PubMed1983

Organization of catecholamine and serotonin-immunoreactive neurons in the corpora pedunculata of the desert locust, Schistocerca gregaria Forsk.

Catecholamine (CA)-containing and serotonin (5-HT)-immunoreactive fibers were shown in the mushroom body of Schistocerca gregaria. Both fiber systems occupy distinct areas in the mushroom body. None of these amines could be detected in the Kenyon cell bodies. The 5-HT fibers and many of the CA fibers originate from few extrinsic neurons with large and highly arborized processes concentrated in the commissural pathway linking mushroom bodies to each other and to different brain regions (e.g. optic lobe, lateral neuropil).

Animals↗
PubMed1983

The duct-ligated pancreas transplant and its effect on the islet cellular composition of the host pancreas. A morphometric analysis.

Rats rendered diabetic by streptozotocin were subjected to pancreas transplantation. After twenty weeks, the duct-ligated pancreas transplant was studied morphometrically to determine the effect of duct occlusion on the various cell populations of the islets. Concomitantly, the streptozotocin-treated host pancreas was examined for a possible influence of the graft on the diabetic pattern of islet cell population. Twenty weeks after pancreas transplantation, the volume fractions of insulin, glucagon, somatostatin and pancreatic polypeptide cells in the graft islets did not differ from those of the normal control pancreas. In the pancreas of nontransplanted diabetic rats, insulin-positive B cells were reduced from 60-65% to less than 10% of the islet volume, whereas non-B cells were significantly increased in volume density. The changes in fractional volume of the various islet cells correlated fairly well with changes in plasma concentration of the corresponding pancreas hormones. In the recipient's own pancreas, the relative volumes of glucagon and somatostatin cells were unaffected by the pancreas transplant. However, the insulin cell mass was significantly increased, and comprised about 20% of the islet volume, while cells containing pancreatic polypeptide were found only sporadically.

Animals↗
PubMed1983

Nerve fibers in the gut and pancreas of the rat displaying neuropeptide-Y immunoreactivity. Intrinsic and extrinsic origin.

Immunoreactive neuropeptide Y (NPY) was demonstrated in neuronal elements in the gut and pancreas of the rat. Immunoreactive endocrine cells could not be detected. The occurrence of NPY-containing nerve-cell bodies in the submucosal and myenteric ganglia indicates an intrinsic origin of the NPY fibers. However, an additional extrinsic supply of NPY fibers is suggested by the finding that abdominal sympathectomy caused the disappearance of some NPY fibers, notably those around blood vessels. The distribution of NPY fibers in all layers of the gut wall suggests multiple functions of NPY, including a role in the regulation of intramural neuronal activities, smooth muscle tone, and local blood flow.

Animals↗
PubMed1983

Distribution, pathways and reactions to drug treatment of nerves with neuropeptide Y- and pancreatic polypeptide-like immunoreactivity in the guinea-pig digestive tract.

Pancreatic polypeptide-like immunoreactivity (PPLI) has been localized in nerves of the guinea-pig stomach and intestine with the use of antibodies raised against avian, bovine and human pancreatic polypeptide (PP), the C-terminal hexapeptide of mammalian PP, and against the related peptide, NPY. Each of the antibodies revealed the same population of neurones. Reactive cell bodies were found in both myenteric (5% of all neurones) and submucous ganglia (26% of all neurones) of the small intestine, and varicose processes were observed in the myenteric plexus, circular muscle, mucosa and around arterioles. The nerves were unaffected by bilateral subdiaphragmatic truncal vagotomy, but the staining of the periarterial nerves disappeared after treatment of animals with reserpine or 6-hydroxydopamine and was also absent after mesenteric nerves had been cut and allowed to degenerate. Vascular nerves showing immunoreactivity for dopamine beta-hydroxylase and PPLI had the same distribution. It is concluded that PPLI is located in periarterial noradrenergic nerves. However, other noradrenergic nerves in the intestine do not show PPLI, and PPLI also occurs in nerves that are not noradrenergic. Analysis of changes in the distribution of terminals after microsurgical lesions of pathways in the small intestine showed that processes of myenteric PP-nerve cells provide terminals in the underlying circular muscle and in myenteric ganglia up to about 2 mm more anal. Submucous PP-cell bodies provide terminals to the mucosa.

Animals↗
PubMed1983

Substance-P-containing nerve fibers in the nasal mucosa.

Nerve fibers displaying SP immunoreactivity were detected in the nasal mucosa of several mammals. The fibers were seen around small blood vessels, seromucous glands, and beneath and sometimes within the surface epithelium. In the pterygopalatine ganglion and the trigeminal ganglion, known to innervate the nasal mucosa, SP-positive nerve cell bodies were seen. Sympathetic denervation with 6-hydroxydopamine (6-OHDA) or bilateral cervical sympathectomy did not visibly affect the distribution of SP fibers in the nasal mucosa in mice or rats. The findings are compatible with the view that the bulk of SP fibers to the nasal mucosa derive from the trigeminal ganglion with a possible contribution from the pterygopalatine ganglion.

Acetylcholinesterase↗
PubMed1983

Immunohistochemical localization of substance P, vasoactive intestinal polypeptide and gastrin-releasing peptide in vas deferens and seminal vesicle, and the effect of these and eight other neuropeptides on resting tension and neurally evoked contractile activity.

Immunohistochemical studies of the vas deferens and seminal vesicle of mouse, guinea-pig, and rabbit showed the presence of nerve fibres containing vasoactive intestinal polypeptide (VIP), substance P (SP), and gastrin-releasing peptide (GRP) supplying the smooth muscle layers as well as blood vessels. The nerve supply was better developed in the seminal vesicle than in the vas deferens. The motor activity of the vas deferens and seminal vesicle of the guinea-pig was studied in vitro. The vas deferens responded to transmural electrical stimulation with a twitch followed by a slow contraction. The twitch was blocked by guanethidine and tetrodotoxin, but not by atropine, propranolol, phenoxybenzamine, or fluphenazine. The slow contraction exhibited features of an alpha-receptor-mediated response. SP, physalaemin and eledoisin contracted the smooth muscle and also potentiated the twitch response to electrical nerve stimulation in a concentration-dependent manner. The SP blocking agent, (D-Pro2,D-Trp7,9)-SP, affected neither the resting tension nor the response to electrical stimulation. It is therefore suggested that the SP fibres act mainly prejunctionally. VIP, Leu-enkephalin, cholecystokinin octapeptide (CCK-8), angiotensin II, vasopressin, neurotensin, bombesin, and GRP had no effect on either the resting tension or the response to electrical nerve stimulation. The seminal vesicle responded to electrical stimulation with a contraction which was unimpaired by atropine, propranolol, phenoxybenzamine, and guanethidine, but abolished by tetrodotoxin. Hence, this contraction is mediated by a non-adrenergic, non-cholinergic neurotransmitter. Bombesin, GRP, SP, physalaemin and eledoisin contracted the smooth muscle and potentiated the response to electrical stimulation. VIP, Leu-enkephalin, CCK-8, angiotensin II, vasopressin, and neurotensin had no effect on the resting tension or on the response to transmural electrical stimulation. The SP antagonist abolished the contraction elicited by SP but did not influence the response to nerve stimulation. The results suggest that the SP and GRP nerves may have prejunctional and facilitating postjunctional effects in the seminal vesicle.

Animals↗
PubMed1983

Neuronal gastrin-releasing peptide in the mammalian gut and pancreas.

Immunoreactive gastrin releasing peptide (GRP) was demonstrated in neuronal elements in the porcine pancreas and in the gut of several mammals. Immunoreactive endocrine cells could not be detected. The results of radioimmunochemical analysis agreed well with those of immunocytochemistry. The occurrence of gastrin-releasing peptide-containing nerve cell bodies in the myenteric ganglia all along the gut indicates that gastrin-releasing peptide fibers are intramural in origin. The distribution of gastrin-releasing peptide fibers in all layers of the gut wall suggests multiple functions of gastrin-releasing peptide, including a role in the regulation of intramural neuronal activities, smooth muscle tone and in secretory and absorptive processes.

Animals↗
PubMed1983

Nerve fibres containing gastrin-releasing peptide around pial vessels.

Nerve fibres containing immunoreactive gastrin-releasing peptide (GRP) were demonstrated around pial blood vessels of cat, guinea pig, rat, and mouse. A sparse supply was found around spinal cord blood vessels, whereas the choroid plexus seemed to be devoid of GRP fibres. Sympathectomy did not affect the number or distribution of the GRP fibres. The administration of neither GRP nor its closely related analogue, bombesin, contracted or dilated feline pial arteries in vitro.

Animals↗