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Biomedical subjects

F Sundler

Publications and source records attributed to F Sundler.

At least 469 records · Page 26Linked to original sources
PubMed1980

Presence and influence of cholinergic nerves in the human thyroid.

There is evidence that the sympathetic nervous system exerts a control on human thyroid function via an adrenergic innervation of follicle cells. The present study demonstrates that cholinergic nerve fibers also reach follicle cells in the normal human thyroid. In addition, cholinergic agents were found to enhance cGMP accumulation in human thyroid tissue. This effect was blocked by atropine, a muscarinic receptor antagonist, but not by d-tubocurarine, a nicotinic receptor antagonist. These results provide morphological and biochemical arguments supporting a role of the parasympathetic nervous system in the regulation of thyroid function in man.

Acetylcholine↗
PubMed1980

Vasoactive intestinal polypeptide (VIP) in epithelial cells of the gut mucosa of an elasmobranchian cartilaginous fish, the ray.

As part of study of the phylogeny of VIP, it was observed that the colonic mucosa of the cartilaginous fish, Raja radiata and Raja clavata, contained numerous epithelial cells, obviously of closed type, displaying intense VIP immunoreactivity. Accordingly, high concentrations of VIP were found by radioimmunoassay. At the ultrastructural level, the VIP cells were characterized by the presence of highly electron dense secretory granules. The colonic mucosa of the ray may be a good source for the isolation of an early VIP.

Animals↗
PubMed1980

Occurrence of VIP nerves in mammalian dental pulps.

Vasoactive intestinal polypeptide (VIP), a neuropeptide with possible neurotransmitter function, was demonstrating in nerves of dental pulps of several mammals including man. The VIP containing nerves were observed around blood vessels and as single terminals in the pulpal stroma. In view of the potent vasodilatory actions of VIP it is conceivable that pulpal VIP nerves take part in the regulation of local blood flow.

Animals↗
PubMed1980

Peptidergic (enkephalin) innervation of the mammalian esophagus.

Enkephalin-like immunoreactivity was demonstrated in nerves in the esophagus of guinea-pig, opossum, cat, pig, monkey, and humans. Immunoreactive nerves were found in the external muscle layer and in the muscularis mucosae. In the myenteric plexus immunoreactive nerve fibers were numerous; immunoreactive nerve cell bodies were observed only occassionally. Enkephalin nerves appeared early (the 7th wk of gestation) in porcine fetuses; at this stage the nerves were confined to the myenteric plexus. Motor effects of enkephalin were studied on segments from circular smooth muscle of cat esophagus. Enkephalin inhibited electrically induced contractions in a dose-dependent manner. This effect was blocked by naloxone. The results suggest that enkephalin nerves may be involved in the regulation of esophageal motility. Like enkephalin, bretylium (a blocker of adrenergic transmission) and phentolamine (on alpha-adrenergic blocker) prevented the contractile response to electrical stimulation. With smooth muscle strips from reserpinized cats the response to electrical field stimulation was abolished, but not the response to norepinephrine. Taken together, the results suggest that neuronal enkephalin in the esophagus functions as a modulator of adrenergic transmission.

Adrenergic Fibers↗
PubMed1980

Vasoactive intestinal peptide nerves in ocular and orbital structures of the cat.

Vasoactive intestinal polypeptide (VIP), a neuronal peptide of ubiquitous occurrence in the body, is known to have strong vasodilatory effects and to promote secretion from many exocrine glands. Nerves displaying VIP immunoreactivity (VIP nerves) were detected in several orbital structures of the cat. Such nerves were numerous in the lacrimal glands and somewhat less numerous in the Harderian glands and the tarsal glands. The nerves surrounded glandular acini and small blood vessels. Intraocularly, VIP nerves were seen in the ciliary processes, in the posterior third of the ciliary muscle, and around small to medium-sized blood vessels in the posterior uvea. VIP nerve fibers were absent from vessels in the anterior uvea. This distribution may explain why intracranial stimulation in the oculomotor nerve exit region dilates the vessels of the choroid but not those of the iris. A large number of VIP-immunoreactive nerve cell bodies were observed in the pterygopalatine ganglion. Extirpation of this ganglion resulted in the disappearance of VIP nerves from the intraocular structures and from the lacrimal and Harderian glands. Removal of the superior cervical ganglion and the ciliary ganglion did not affect the VIP nerve supply. The results suggest that the VIP nerves originate in the pterygopalatine ganglion.

Animals↗
PubMed1979

Development of vasoactive intestinal polypeptide (VIP) containing neurones in the rat brain.

The development of VIP-containing neurones in the rat CNS and duodenum has been studied using a specific radioimmunoassay and immunohistochemistry. In the brain, VIP immunoreactivity appears entirely postnatally, while VIP in peripheral neurones in the duodenum was present before birth. The developmental changes observed in cerebral cortex appear to represent the maturation of a population of intrinsic cortical interneurones which contain VIP. These neurones develop entirely after birth. They are first seen in deep cortical layers, but later spread out into all cortical layers, particularly layers II--IV. Changes in the intensity of VIP cell body fluorescence can be correlated with changes in VIP content in the cortex measured by radioimmunoassay. Thus VIP forms a unique chemical marker for studying the maturation of a cortical neurone.

Age Factors↗
PubMed1979

Gut-type glucagon immunoreactivity in nerves of the rat brain.

Nerve fibers reacting with antisera demonstrating gut-type glucagon were numerous in certain areas of hypothalamus and thalamus but absent from neocortex and hippocampus. They did not react with glucagon antisera specific for pancreatic type glucagon. Immunoreactive cell bodies were not observed.

Animals↗
PubMed1979

Growth hormone-like immunoreactivity in gastrin cells and gastrinomas.

Growth hormone (GH)-immunoreactive material was found to occur in the antral gastrin cells and in scattered cells of the pancreatic islets in several mammalian species, including man. Examination of gastrinomas revealed the majority of tumour cells to display GH-like immunoreactivity.

Animals↗
PubMed1979

Topography of somatostatin cells in the stomach of the rat: possible functional significance.

Somatostatin cells in the stomach of the rat have a characteristic shape and distribution. In the antral mucosa they occur together with gastrin cells and enterochromaffin cells at the base of the glands. In the oxyntic mucosa they are scattered along the entire glands with some predominance in the zone of parietal cells. Throughout the gastric mucosa the somatostatin cells possess long and slender processes that emerge from the base of the cell and end in club-like swellings. Such processes appear to contact a certain proportion of neighbouring gastrin cells in the antral mucosa and parietal cells in the oxyntic mucosa. Exogenous somatostatin given by intravenous infusion to conscious rats counteracted the release of gastrin stimulated by feeding, elevated antral pH or vagal excitation. Gastrin causes parietal cells to secrete HCl and endocrine cells in the oxyntic mucosa to mobilise and synthesise histamine. Somatostatin is known to block the respone of the parietal cells to gastrin. In contrast, somatostatin did not block the response of the histamine-storing endocrine cells to gastrin, perhaps because these endocrine cells lack receptors to somatostatin. Conceivably, somatostatin in the gastric mucosa has a paracrine mode of action. The observations of the present study suggest that somatostatin may affect some, but not all of the various cell types in the stomach. Under physiological conditions this selectivity may be achieved in the following ways: 1) Communication may be based on direct cell-to-cell contact. 2) Only certain cell types are supplied with somatostatin receptors.

Animals↗
PubMed1979

Immunoreactive pancreatic polypeptide (PP) occurs in the central and peripheral nervous system: preliminary immunocytochemical observations.

Pancreatic polypeptide (PP) is a candidate hormone of unknown physiological significance. It is produced by a population of endocrine cells in the pancreas. In the present study a PP-like peptide was found to occur in the mammalian and avian central andperipheral nervous systems. Immunoreactive nerve fibres and nerve cell bodies were widely distributed in the brain. Dense accumulations of nerve fibres occurred in the following areas: nucleus accumbens, interstitial nucleus of the stria terminalis, para- and periventricular hypothalamic nuclei, and medical preoptic area. In addition, nerve fibres were regularly seen in cortical areas. Immunoreactive perikarya were observed in the following regions: cortex, nucleus accumbens, neostriatum and septum. In the gut, immunoreactive nerve fibers were distributed in the myenteric plexus, in smooth muscle, around blood vessels, and in the core of the villi. Immunoreactive perikarya occurred in the submucosal and myenteric plexus, suggesting that PP immunonal PP-like peptide could be demonstrated with an antiserum raised against avian PP, but not with those raised against bovine or human PP. Thus, neuronal PP is distinct from the PP that occurs in pancreatic endocrine cells.

Animals↗
PubMed1979

Effect of antrum exclusion on endocrine cells of rat stomach.

1. Following antrum exclusion the serum gastrin concentration was raised and independent of the prandial state. The antral gastrin concentration and number of gastrin cells were greatly lowered. 2. The histamine content and the number of histamine-storing endocrine ('entero-chromaffin-like') cells in the oxyntic mucosa was almost doubled and the mucosal histidine decarboxylase activity was greatly elevated following antrum exclusion. 3. At the ultrastructural level both types of histamine-storing endocrine cells (ECL and A-like) were found to be enlarged and to have a reduced number of granules per unit cytoplasm. These changes are compatible with an increased secretory activity. The G (gastrin) cells were not increased in size but their granule volume density was lowered. 4. We propose that antrum exclusion results in uninhibited gastrin release causing profound changes in the histamine-storing endocrine cells of the oxyntic mucosa. The cells respond to the hypergastrinemia by an increase in functional activity (activation of histidine decarboxylase and reduction of granule volume density) as well as by an increase in number and size.

Animals↗