Remarkable adrenergic nerves in the exocrine pancreas

Summary The adrenergic nerves in the pancreas of mice, rats, guinea-pigs, rabbits, and cats were investigated with the fluorescence method of Falck and Hillarp. The relations between the adrenergic fibres and the vessels were studied by the injection of india ink into the vessels.Besides the normal manifestation of adrenergic fibres at the large vessels, some vessels of capillary size were also accompanied by adrenergic fibres. These fibres had a very weak fluorescence, and showed up regularly only when the animal had been treated with Nialamide and L-DOPA or dopamine to increase the catecholamine content of the adrenergic fibres. The weakness of the fluorescence is perhaps due to low transmitter concentration or to small size of the nerve fibres, or to both. A rough estimate indicated that either the transmitter concentration of the nerve fibre is at least approximately 100 times below that seen in adrenergic nerves in other tissues, or that the radius of the varicosities of the nerve fibres is less than 0.2 . Neither alternative has previously been recognized.The secretory acini of the pancreas seem to lack a direct adrenergic supply. In the intrapancreatic ganglia, non-fluorescent nerve cells were reached by adrenergic terminals. No adrenergic nerve cells were detected in the pancreas of rats and cats. Small intensely fluorescent catecholamine-containing cells were observed in connexion with the intrapancreatic ganglia of rats.The research reported in this document has been sponsored by the Air Force Office of Scientific Research under grant AF EOAR 67-15 through the European Office of Aerospace Research (OAR), United States Air Force, by the United States Public Health Service (grant NB 06701-01) by the Swedish Medical Research Council (project B 67-12X-712-02A), and by the Faculty of Medicine, University of Lund, Sweden.     

Degeneration of adrenergic nerves in the urinary bladder during pregnancy

The adrenergic innervation of the urinary bladder of normal female and pregnant rats has been studied using a fluorescence histochemical method. The bladder is richly innervated by adrenergic nerve fibres as is evidenced by the presence of numerous adrenergic nerves in the adventitia, musculosa and submucosa. However, adrenergic nerve cells could not be observed. During pregnancy, adrenergic nerve fibres showed signs of degeneration, as most of the nerve fibres disappeared and the surviving fibres were much swollen. 10 days after parturition the pattern and density of adrenergic innervation became almost similar to those of the control animals.     

A method for the localization of adrenergic nerves during early development

Summary Problems associated with the low intensity and fast fading of the formaldehydeinduced fluorescence of adrenergic nerves in young foetal human and rat gut have been overcome by loading the nerves with a primary catecholamine. This has been achieved by incubating the tissue, before freeze-drying, in Krebs solution containing added noradrenaline or -methyl-noradrenaline. With this method fluorescent nerves have been revealed at a stage before any were demonstrable by normal procedures.This work was supported by the Australian Research Grants Committee and the National Heart Foundation of Australia. One of us (J. B. R.) was in receipt of a Commonwealth of Australia Postgraduate Award. We thank Prof. C. Wood for the human foetal material obtained, by hysterotomy, at legal terminations of pregnancy.     

Fluorescence microscopical demonstration of 5-hydroxydopamine in adrenergic nerves

Summary It is demonstrated that 5-hydroxydopamine (5HDA) is capable of forming highly fluorescent products with formaldehyde under conditions suitable for histochemical analyses. Prom absorptiometric and fluorometric studies it is reasonable to assume that the fluorophores formed are isoquinolines, in analogy with the reaction between, e.g., dopamine and formaldehyde. The reaction proceeds readily in protein layers and actual nerve terminals in tissues, allowing demonstration and identification of 5HDA in tissue structures. From studies on rat irides it is demonstrated that only adrenergic terminals take up 5HDA in demonstrable amounts.This work was supported by grants from the Swedish Medical Research Council (B69-14X-712-04C and B69-14X-2321-02), Knut och Alice Wallenbergs stiftelse and the Faculty of Medicine, University of Lund.     

The distribution of peptide-containing nerves in the synovia of the cat knee joint.

Synovial capsule in cats is extensively innervated by a network with axonal diameter ranging from 0.6-3 microns according to its position and neuropeptide content. Nerve markers such as Neuron Specific Enolase (NSE) and Neurofilament triplet protein (NF) could be observed only when the axonal fibre attained a critical diameter of over the 3 microns limit. The relatively thick fibres (1-3 microns) show positive immunoreactivity for Substance P (SP), 5-hydroxytryptamine (5-HT), and Vasoactive Intestinal Peptide (VIP), and seldom coreact with NSE and NF, whereas, the thinnest fibres (0.6-0.8 microns) characterized to contain either Methionine or Leucine Enkephalin (M-Enk, L-Enk) did not coreact positively with axonal markers. We found that different anesthetics may effect variably the immunoreactivity of some neuropeptides (SP, L-Enk, 5-HT) while others (VIP, M-Enk) remained unaffected. Based on our data and the few reported ones in the pertinent literature, it is judged that urethane is the anesthetic of choice in experimental studies of neuropeptides. Our findings of isolated positive immunoreactive cell bodies to enkephalin in synovia might suggest the presence of intrinsic relay system, where the enkephalin acts as suppressor of SP and VIP release from the sunovium nerve terminals. Such a local inter-relationship between different neuropeptide systems might have a practical role on the understanding of the pathogenesis of different arthritic processes as well as therapeutic strategy in the future.     

Distribution of myelinated nerves in ascending nerves and myenteric plexus of cat colon

The parts of the colon differ in motor function and in responses to extrinsic and intrinsic nerve stimulation. The distribution of myelinated nerve fibers in the colonic myenteric plexus is not known. Because these fibers might be largely extrinsic in origin, their distribution might indicate the domain of influence of extrinsic nerves and help to explain the different behaviors of the different parts of the colon. Myelinated fibers were examined by electron microscopy in cross sections of the ascending nerves and in myelin-stained whole-mount preparations in the colon. The ascending nerves are much like one another. They have the structure of peripheral nerves, not that of myenteric plexus. The proportion of myelinated fibers in the ascending nerves declines rostrad with no uniform change in total nerve fiber number. Cross-sectional areas of ascending nerves, 3,304 to 7,448 microns 2; total number of nerve fibers per profile, 703-2,651; and mean myelin coat thickness, 0.45 +/- 0.01 micron, do not change uniformly along the ascending nerves. Myelinated fibers are about 2% of total fibers in the extramural colonic nerves, 7-9% in the ascending nerves in the sigmoid colon, and 2-3% at the rostrad ends of the ascending nerves in the transverse colon. Blood vessels lie at the core of each ascending nerve and on the nerve sheath. Myelinated fibers in the ascending nerves degenerate after section of colonic branches of the pelvic plexus and after section of the pudendal nerves, indicating that myelinated nerves reach the colon through both pathways.(ABSTRACT TRUNCATED AT 250 WORDS)     

Combined fluorescence histochemistry and 3h-noradrenaline measurements of adrenergic nerves

Summary A method is described which combines the histochemical fluorescence technique of Falck and Hillarp with isotope measurements in the same pieces of tissue. Tissue pieces incubated in isotope solutions were treated for fluorescence microscopy and examined. They were then removed from the microscopical slides, and the radioactivity determined. It was shown that NA¹ content and estimated fluorescence intensity were well correlated. The procedure devised is of special value when isotope measurements are needed of structures which can be safely identified only in the fluorescence microscope, and it has been used for quantitative estimations of adrenergic innervation.Abbreviations used Na noradrenaline - cpm counts per minute - dpm desintegrations per minute     

A method for the demonstration of adrenergic nerve fibres in peripheral nerves

Summary The adrenergic nerve fibres running from the ganglia to the innervated tissues usually have too low a content of noradrenaline to be clearly visualized with the histochemical fluorescence method of Falck and Hillarp. They can easily be demonstrated, however, as early as 24 hours after axotomy (crushing or constriction of the nerves) due to the rapid accumulation of what is probably noradrenaline taking place proximally to the lesion. The fibres can be visualized even more clearly if axotomy is combined with the administration of l-dopa and with monoamine oxidase inhibition. In this way the presence, distribution and direction of adrenergic fibres can be directly studied in peripheral nerves.For generous supplies of drugs we are indepted to Swedish Ciba, Stockholm (reserpine) and Swedish Pfizer, Stockholm (nialamide). The investigation has been supported by research grants from the United States Public Health Service (NB 02854-04), the Swedish Medical Research Council, and Knut and Alice Wallenbergs Foundation.     

Oscillatory potentials of the cat retina: effects of adrenergic drugs

When reserpine was used as a monoaminergic depletion agent, a diminution or suppression of certain components of the oscillatory potentials of the electroretinogram of the cat was observed. Administration of L-Dopa to previously reserpinized cats restored the altered OP components. The possible interference of systematic disturbances provoked by the drugs was studied by means of artificial variations of blood pressure. Results reported in this paper suggest that reserpine and L-Dopa are acting on catecholamine-dependent retinal structures, probably the dopamine-containing population of amacrine cells. An hypothesis is advanced concerning the possible role of tangential structures in the generation of the oscillatory potentials of the retina.