Pancreatic amylase release in chronically pilocarpine-treated rats

The neuronal and glial release of (³H)-GABA from rabbit retina has been studied. The results indicate, that neither are there any glutamate, aspartate or glycine receptors on the GABA accumulating neurons, nor any GABA autoreceptors. (³H)-GABA was found to be released by 40 mM K⁺ from retinal neurons, but not from glia, and the release was not dependent on extracellular Ca⁺⁺. This indicates a release from a non vesicular transmitter pool. Ouabain has been proposed as a pharmacological tool for studying the release of (³H)-GABA located in neuronal cytoplasm. However, it induced an increased release of (³H)-GABA from both neurons and glia and it is therefore unlikely that it can be used for the specific purpose of studying release from neuronal cytoplasm.     

The Chronically Reserpinized Rat Disturbed Energy Metabolism in the Submandibular Gland

Some of the enzymes and metabolites of the glyconeogenetic pathway, ATP and creatine phosphate were investigated in the submandibular gland of reserpinized rats, and compared to those of control rats. Decreased activities of malic enzyme (p<0.005) and glucose-6-phosphatase (p<0.001) were found, while the activities of fructose-1,6-diphosphatase and malate dehydrogenase were not significantly changed. No activity of pyruvate carboxylase or phosphoenolpyruvate carboxylase was detected. Oxaloacetate ( p <0.01), malate ( p <0.005) and citrate ( p <0.005) were found in decreased concentrations and fructose-6-phosphate in increased concentration in the submandibular glands of reserpinized rats. Decreased concentration of ATP ( p <0.01) was found whereas the concentration of creatine phosphate was increased ( p <0.05). The activity of creatinephosphokinase was decreased ( p <0.005). These findings show a disturbance of high-energy phosphate compounds content and a possible acidosis in the submandibular gland of this animal model for cystic fibrosis.     

EFFECTS OF CYSTIC FIBROSIS SERUM AND CELL CULTURE MEDIUM ON THE MUCOCILIARY ACTIVITY OF THE RESPIRATORY TRACT

ABSTRACT. Tegner, H., Ceder, O., Roomans, G. M., Kollberg, H. and Torcmalm, N. G. (Department of Otolaryngology, University of Lund, Malmo General Hospital, Malmo, Department of Pediatrics, University of Umea, Umea, and the Wenner-Gren Institute, University of Stockholm, Stockholm, Sweden). Effects of cystic fibrosis serum and cell culture medium on the mucociliary activity of the respiratory tract. Acta Paediatr Scand, 70:629,.–As previously reported a cystic fibrosis factor (CFF) is associated with the dyskinetic ciliary motion induced by serum and cell culture medium from patients with cystic fibrosis (CF). In this study a sensitive, standardized method, for the photoelectric recording of mucociliary activity was used to examine the effect of sera and media from cell cultures taken from patients with CF and healthy controls, on the mucociliary activity of rabbit trachea in vitro. No signs of decreased mucociliary activity were observed and electron microscopy showed normal ultrastructure and orientation of cilia.     

Progesterone,oestradiol and oxytocin and their in vitro effect on maintaining the number of gap junction plaques in human myometrium at term

Previous studies by electron microscopy and laser confocal microscopy of immuno-histochemically stained sections have shown that during pregnancy the extent of gap junction formation in human myometrium is low, but that an increase occurs in the active stages of labour despite a high concentration of progesterone in maternal blood. The present investigation focused on the effect of in vitro exposure of isolated myometrical tissue to progesterone, oestradiol and oxytocin, on the number of gap junction plaques in human myometrium at term. Myometrial biopsies were obtained at term from 13 pregnant women who had an elective caesarean section in the 37th or 40th week of pregnancy. The biopsies were immersed immediately in Hepes buffer and buffer containing 0.5, 5.0 μg mL^-1 of progesterone, and 0.1 μg mL^-1 of oestradiol. The muscle biopsies were trimmed under a stereo microscope into strips along the bundles of smooth muscle cells and mounted in tissue baths, superfused with Hepes buffer supplemented with glucose (0.01 mm ); subsequently the strips were exposed to buffer containing different concentrations of progesterone, oestradiol and oxytocin. Incubation of the muscle strips for 180 min resulted in a significant decrease of the number of gap junctions (P <0.01). Neither oestradiol or oxytocin, alone or in combination, had a significant effect on the maintenance of the number of gap junctions. The progesterone concentration of 5.0 μg mL^-1, combined with oxytocin, and with or without oestradiol had a significantly positive effect on the number of gap junction plaques in strips of human myometrium at term (P<0.05 vs. buffer alone). The high concentration of progesterone in the superfusion medium during in vitro experiments may be responsible for the maintenance of high numbers of gap junction complexes in term human myometrium. This finding is of interest in the light of findings of persisting high progesterone levels in maternal blood during labour.     

cAMP-induced chloride transport in NCL-SG3 sweat gland cells

cAMP-induced ion transport in a human sweat gland cell line, NCL-SG3, was investigated by X-ray microanalysis and patch-clamp technique. Stimulation with cAMP caused a decrease in the cellular Cl and K. cAMP had no significant effect on the intracellular Na and Ca. Chloride channel blockers (9-AC, DPC and NPPB) inhibited the cAMP-induced chloride efflux. In patch-clamp experiments the inward current increased over a period of 5–15 min on addition of membrane-permeable cAMP in 66% of the attempts when the cell was held at 0 mV and pulsed to negative membrane potentials. The inward current was completely blocked by chloride channel blockers. Washout reversed the effect of cAMP. The inward current was not diminished by substitution of impermeable cations for Na in the bath and was insensitive to TEA (tetraethylammoniumchloride). It is concluded that the inward current is mainly a chloride current. Cystic fibrosis transmembrane regulator (CFTR) could not be demonstrated in the NCL-SG3 cells. It is therefore possible that the chloride efflux is mediated by other types of chloride channels.     

ELECTROLYTES IN NAILS ANALYSED BY X-RAY MICROANALYSIS IN ELECTRON MICROSCOPY Considerations on a New Method for the Diagnosis of Cystic Fibrosis

ABSTRACT. Patients with cystic fibrosis (CF) have an increased concentration of sodium in their nails. Hitherto, only neutron activation analysis has been considered for the diagnosis of cystic fibrosis by analysis of electrolytes in nails. It has been thoroughly tested methodologically and clinically. However, the intrinsic advantages of X-ray microanalysis and the results obtained in this study suggest that this method, after further testing, may be a useful diagnostic aid for cystic fibrosis. In comparison with neutron activation analysis, X-ray micro-analysis has the advantage of simultaneously giving the concentrations of several elements and may be accessible at any hospital with an electron microscope fitted with the necessary equipment. Nails of CF-patients are here shown to have increased concentrations of Na, K and Cl, which will make the diagnosis of cystic fibrosis more reliable. The possibility of using sulphur as a reference element may eliminate the weighing procedure necessary in neutron activation analysis.     

X-ray micro-analysis of cultured respiratory epithelial cells from patients with cystic fibrosis

X-ray micro-analysis was carried out on cultured respiratory cells from polyps removed from individuals with and without cystic fibrosis (CF). In a first set of experiments, proper experimental conditions were established. Washing the cells with 300 mmol 1^-1 mannitol in distilled water was found to give the best removal of the culture medium. The elemental concentrations stabilized in about 10 min after the start of the preincubation. Intracellular [Na] and [Cl] increased slightly with increasing passage number, whereas intracellular [K] decreased. Under resting conditions there were no significant differences in elemental content between CF and control cells, and there were no indications for abnormally high total [Ca] in CF cells. In normal cells, stimulation with a cAMP-analogue resulted in a decrease of cellular [CI], whereas in CF cells an increase was measured. Exposure of both normal and CF cells to ouabain resulted in decreased [K] and increased [Na] and [CI] level. The calcium ionophore A23187 had a similar effect on normal cells but did not affect CF cells markedly. Application of amiloride to the apical side of the cells resulted in a decrease of cellular [Na] in CF cells, whereas [Na] in control cells was not affected. The results correspond with what is known about the defective cAMP-regulated transepithelial Cl-transport in CF cells. The effect of the calcium ionophore on cellular electrolyte content is more complicated and may be the result of two separate effects: efflux of Cl^- via a Ca²⁺-dependent mechanism and inhibition of the Na⁺-K⁺-ATPase by intracellular Ca²⁺ ions causing an influx of Na⁺ and Cl^- ions.     

Effects of UTP on Na+, Cl− and K+ transport in primary cultures from human sweat gland coils

In six healthy human subjects we compared changes in the strength of Hoffmann (H), short latency (30–55 ms) and long latency (55–100 ms) stretch reflexes of flexor carpi radialis (FCR) muscle during movement and isometric contractions. In one set of experiments, stretches were imposed to the wrist during voluntarily tracked sinusoidal movement and during matched isometric contractions to compare short and long latency stretch reflex responses. In the second set, H-reflexes were compared during similar matched conditions. All reflexes decreased significantly (P < 0.05) during the voluntary tracking movement. The H-reflex was reduced during the wrist flexion, on average, by 33% of its value obtained during the isometric condition. Compared with their values during isometric conditions, the short latency stretch reflex and long latency stretch reflex during movement were reduced by 52 and 40%, respectively. From the pattern changes of the stretch reflexes and the H-reflex, a movement-induced presynaptic inhibition combined with pronounced muscle spindle unloading is proposed to play an important role in decreasing the strength of the stretch reflexes during the tracking task as compared with a matched isometric contraction.     

Response of myocardial cellular energy metabolism to variation of buffer composition during open-chest experimental cardiopulmonary resuscitation in the pig

The aim of the present study was to investigate possible relationships in piglets between myocardial energy-related metabolites and intracellular electrolytes during open-chest cardiopulmonary resuscitation (OCCPR) supplemented by the administration of alkaline buffers with varying sodium content. Our hypothesis was that an increasing myocardial intracellular sodium content would decrease the intracellular energy stores. In addition to haemodynamics, acid–base and blood gas variables were analysed, and myocardial biopsies were collected before and during OCCPR as well as after the return of spontaneous circulation. After a period of 4 min of untreated ventricular fibrillation (VF), 25 piglets were randomly allocated to one of four groups: OCCPR with normal saline (n = 5); OCCPR with sodium bicarbonate (SB) (n = 7); OCCPR with Tris buffer mixture (TBM) (n = 7); and a totally untreated control group (n = 6). The results showed that 4 min of untreated VF almost eradicated creatine phosphate (CrP) and that the ATP/ADP ratio decreased to 1.5–2.0. During OCCPR with normal saline, the myocardial content of CrP increased, whereas lactate, ATP and ADP levelled off and AMP decreased, causing an increased ATP/ADP ratio. The adenosine and inosine contents increased, whereas inosine monophosphate was unchanged at a low level, the adenosine and inosine contents being inversely correlated with the total content of adenine nucleotides. In both buffered groups, the increase in most energy-related metabolites (CrP, ATP, ADP, AMP and the ATP/ADP quotient) was less and in lactate more pronounced than in the group not being buffered, with no difference between the groups receiving SB or TBM. Although the intracellular potassium content was unaltered, the sodium, chloride and calcium concentrations increased, more so in the group receiving SB. The intracellular content of sodium was correlated with that of calcium. Thus, buffering increased the myocardial AMP degradation during OCCPR by increasing the flux via the 5′-nucleotidase reaction, and SB increased the intracellular contents of sodium and calcium to a greater extent than did TBM.