Effect of angiotensin II on vascular resistance in whole-body perfused dogfish

• 1.1. The effect of angiotensin II (AII), norepinephrine (NE), epinephrine (E) and isoproterenol (ISO) was observed on the branchial and systemic circulations in a whole-body-pump perfused dogfish preparation.
• 2.2. NE and E increased systemic blood flow resistance, but decreased branchial resistance.
• 3.3. ISO decreased both systematic and branchial blood flow resistance.
• 4.4. AII had no significant effect on either branchial or systemic resistance.

     

Ion transport in crab gills: A new method using isolated half platelets of Eriocheir gills in an ussing-type chamber

• 1.1. A half platelet preparation from Chinese crab (Eriocheir sinensis) gill is described which allows electrophysiological investigations of ion transport by gill epithelial monolayer when mounted in a modified Ussing chamber.
• 2.2. The resistance of these preparations equals half that of complete gill platelets (containing the gill epithelium and cuticle twice) indicating that cell damage during preparation of half platelets is negligible.
• 3.3. The transepithelial resistance (resistance of cuticle subtracted previously) was determined to be about 140 Ω cm² when both sides are bathed with identical salines.
• 4.4. Similarities to the results obtained with perfused complete gills demonstrates the reliability of this preparation.
• 5.5. When identical salines are applied on both sides of the epithelium an outside positive transepithelial potential difference (PD_te) up to 40 mV was measured.
• 6.6. The occurrence of such a high PD_te under symmetric conditions and its sensitivity to CN⁻ suggests the PD_te to be generated by active transport processes.

     

Hydrodynamics of water flow in front of and through the gills of skipjack tuna

• 1.1. The structure of the gills of skipjack tuna (Katsuwonus pelamis) is reviewed and the pattern of water flow in front of, and through, the gills is described. The tuna system is attractive for analysis of this type because water flow is continuous rather than pulsatile and the gill system is more rigid than that of other fish. In addition, oxygen uptake rates are the extreme case (i.e. highest values) for water-breathers.
• 2.2. Flow into the slits between the gill bars is rectilinear and nearly uniform, and therefore irrigation at the gill sieve should be nearly uniform.
• 3.3. Reynolds numbers are so low that turbulent flow is unlikely and entrance effects are negligible.

     

The effects of environmental variables on the heart rates of invertebrates

• 1.1. The effects of temperature, salinity and declining O₂ on the heart rates of nine species representing four animal phyla have been investigated in relation to other respiratory paramters.
• 2.2. The effect of temperature on heart rate is at least the same as, and often greater than, the effect of temperature on O₂ consumption, thus providing no evidence that adaptations of the cardiovascular system facilitate metabolic compensations for a temperature change.
• 3.3. Responses to reduced acclimation salinity are very diverse among the various species, permitting no general conclusions about the role of the cardiovascular system in adaptations to estuarine habitats.
• 4.4. At low PO₂ the typical response is bradycardia, which is especially notable in species with a high capacity for anaerobic metabolism. Compensatory tachycardia, the expected response in vertebrates, is very rare in other animal groups.
• 5.5. Estimates of cardiac output from these data generally agree with those obtained according to the Fick principle from blood gas tensions.
• 6.6. The estimates of cardiac output are evaluated in terms of body size, temperature and the design of cardiac muscle, which is fundamentally different in various animal phyla.

     

Skin blood flow in the Wistar-Kyoto rat and the spontaneously hypertensive rat

• 1.1. Using laser Doppler techniques in man, we have previously demonstrated differences in skin blood flow properties at sites with primarily nutritive (NUTR) perfusion, such as the elbow or knee, as compared to sites such as the finger pulp, with predominantly arteriovenous anastomotic (AVA) perfusion.
• 2.2. Basal and heat stimulated flow is greater at AVA sites. In man, blood pressure changes are reflected primarily by changes at AVA rather than NUTR sites.
• 3.3. These blood pressure induced changes affect the red blood cell velocity (VEL) component at AVA sites more than microvascular volume (VOL).
• 4.4. Given these findings in man, we decided to compare skin blood flow properties in a suitable animal model.
• 5.5. We chose the Wistar-Kyoto (WKY) and Spontaneously Hypertensive Rat (SHR) strains, in view of the marked difference in systemic blood pressure in these two related strains.
• 6.6. Skin blood flow varied considerably at different skin sites in the rats. Skin sites with hair covering, on the back and at the base of the tail, showed low basal and heat stimulated blood flow.
• 7.7. In contrast, the plantar surface of the paw behaved similarly to the finger or toe pulps in man, with 3–4-fold higher basal flow than the hair covered areas and a 7–8-fold rise with local heating to 44°C.
• 8.8. Furthermore, there was a 25% greater blood flow at the plantar paw surface in the SHR rats as compared to the WKY rats, corresponding to the 25% higher systemic blood pressure in these animals.
• 9.9. The heat induced increase in flow at the plantar surface of the paw was primarily a result of a marked increase in VEL rather than VOL.
• 10.10. The higher flow at this site in SHR as compared to WKY rats was likewise ascribable to an increase in VEL, VOL being equivalent in the two strains.

     

Vasomotor tone in the dogfish shark

• 1.1. The dogfish, Squalus acanthias, appears to possess arterial vasomotor tone, as evidenced by a significant reduction in arterial blood pressure after administration of an alpha adrenergic blocking agent.
• 2.2. Quick-frezing the entire brain in situ did not reduce arterial pressure, which indicates the vasomotor tone is not generated by neurogenic activity in the brain.
• 3.3. Ganglionic or cholinergic neuro-effector blockade (hexamethonium-atropine) resulted in significant reductions of arterial pressure, which suggests that vasomotor tone is at least partially dependent on neurogenic activity originating in autonomic ganglia or nerve networks.
• 4.4. A hypothesis is advanced that vasomotor tone in this species is maintained by circulating catecholamines, the concentration of which is controlled by peripheral neurogenic activity.
• 5.5. Freezing the brain does not affect the pressor response to angiotensin, thus, the release of catecholamines, which is mediated by angiotensin in the dogfish, is not dependent upon a brain link.

     

Elasmobranch fish (Scyliorhinus canicula and Raja clavata) muscle AMP deaminase: Substrate specificity and effect of EDTA and adenylate energy charge

• 1.1. The AMP deaminases from skeletal muscles of dogfish and skate were shown to be specific to 5′-AMP. Among several adenine nucleotide analogs, only dAMP was deaminated to an extent lower than 5%.
• 2.2. Similar to vertebrates AMP deaminases, these enzymes were inhibited when incubated in the presence of EDTA solutions.
• 3.3. The activity of the enzymes was regulated by adenylic energy charge variations, depending on the size of the total adenine nucleotide pool.
• 4.4. The shape of the adenylate energy charge response curves of the dogfish and skate muscle AMP deaminases do not distinguish the two enzymes.

     

Characterization of the vasoactive intestinal polypeptide (VIP) in the gut of fishes

• 1.1. The presence of VIP was investigated in the dogfish, Scyliorhinus canicula, the ballanwrasse. Lubrus berggylta and the bib. Trisopterus luscus, using a specific radioreceptorassay.
• 2.2. Pure porcine VIP and gut extracts of fishes yielded similar dilution curves.
• 3.3. In the dogfish, the highest concentration of VIP was found in the hindgut. In contrast, in the two teleostei studied, the highest levels of VIP were in the first part of the gut.
• 4.4. The biologically active VIP measured by radioreceptorassay correlated well with the molecule determined using a specific radioimmunoassay.
• 5.5. Our results support the hypothesis of the appearance of VIP early in evolution.

     

Arginase activity in different fish species and tissues

• 1.1. Arginase activity was measured in different tissues from eight species of fish.
• 2.2. Spur dogfish showed a very high arginase activity compared with the other species analysed.
• 3.3. The activity in teleosts was mainly found in tissues of high metabolic activity (liver, kidney and red muscle).

     

Influence of experimental hypothermia on exocrine pancreatic secretion in anaesthetized rabbits

• 1.1. The effects which experimental hypothermia induces on rabbit pancreatic exocrine secretion have been investigated.
• 2.2. The flow of juice and the output of total protein and amylase were lowered during hypothermia.
• 3.3. After rewarming, flow recovered but amylase output remained low.
• 4.4. During hypothermia the sensitivity of the pancreas to secretin and PZ-CCK diminished.

     

The effect of time on physiological changes in eel Anguilla anguilla,induced by lindane

• 1.1. Eel were exposed to a sublethal concentration of lindane (0.335 ppm) for 6, 12, 24, 48, 72 and 96 hr.
• 2.2. Concentrations of glycogen, glucose, lactate, pyruvate and lipids were determined in gill tissue after lindane exposure.
• 3.3. Gill glycogen descreased and glucose levels increased at 6 hr of treatment, lactate and pyruvate concentration increased between 6 and 48 hr. Total lipid values decreased between 6 and 24 hr; thereafter, the levels increased up to 72 hr of exposure.
• 4.4. Clear changes were found in all parameters tested in gill tissues. The observed effects of lindane on metabolism in fish are discussed in relation to acute stress syndrome.

     

Demonstration of specific receptors for calcitonin in isolated trout gill cells

• 1.1. Salmon calcitonin binding by isolated gill cells from rainbow trout, Salmo gairdneri has been investigated.
• 2.2. The calcitonin receptor interaction is time- and temperature-dependent.
• 3.3. 50% of inhibition of the ¹²⁵I labeled calcitonin binding is observed in presence of 1.5 ng/ml unlabeled salmon calcitonin.
• 4.4. Two types of receptors are described: a high affinity-low capacity site and a low affinity-large capacity site.
• 5.5. These studies strongly support the role of calcitonin as a hormone regulating the gill function in physiological conditions.

     

Comparative study on AMP deaminase in gill,muscle and blood of fish

• 1.1. High AMP deaminase activities were determined in the gill of one selachian, Scyliorhinus caniculus, and five teleosts, Anguilla anguilla, Cyprinus carpio, Salmo gairdneri, Perca fluviatilis and Esox lucius.
• 2.2. The highest activity was generally found in skeletal white muscle, except in A. anguilla and S. caniculus.
• 3.3. In s. caniculus a very high AMP deaminase activity was found in the blood where it was shown to be tightly regulated by inorganic phosphate.
• 4.4. Seasonal variations were observed for AMP deaminase activity in gill and white muscle, but also for blood Hb and protein concentration in the three tissues examined.

     

Studies of gluconeogenesis in rat liver using a once-through perfusion technique. Effects of manganese ions

• 1.1. Addition of alanine, ornithine and oleate to livers perfused with low concentrations of lactate produced an increased rate of glucose and urea output associated with a decreased rate of lactate uptake.
• 2.2. The rate of urea output was inversely correlated with the rate of lactate uptake.
• 3.3. In the presence of manganese ions higher rates of glucose output were attained, the rate of lactate uptake was stimulated, but the rate of urea output was unaltered and the correlation between lactate uptake and urea outpu was not observed.

     

Respiratory mechanisms and metabolic adaptations of an intertidal crab,Chasmagnathus granulata (Dana, 1851)

• 1.1. The ventilatory mechanism, gill area, sites of oxygen uptake, oxygen consumption and activity of a crab from south Brazil, Chasmagnathus granulata, were investigated.
• 2.2. The oxygen uptake seems to be restricted to the gill lamellae.
• 3.3. The gill area varies with the wet body weight, being relatively higher in smaller animals. There is not a significative reduction of the gill area in relation to species of the infralittoral zone.
• 4.4. C. granulata presents a mechanism for recirculating the water of its branchial chamber when exposed to atmospheric air.
• 5.5. The oxygen consumption and activity are reduced when the animals are exposed to atmospheric air. The reduction in the oxygen consumption may be related to the poorly adapted respiratory system, while the decrease in activity may be a mechanism for saving energy during this hypoxic period.

     

Development of a Gill Assay Library for Ecological Proteomics of Threespine Sticklebacks (Gasterosteus aculeatus)

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Highlights

• •Construction of threespine stickleback gill assay library using DDA proteomics
• •Population-specific gill proteome signatures of four ecotypes identified by DIA
• •HSP47 and extracellular matrix proteins highly elevated in warm-adapted sticklebacks
• •Inflammasome and proteolytic proteins highly elevated in freshwater sticklebacks

     

Lipid changes in blood serum and tissues of the Egyptian Cobra “Naja haje haje” during the hibernation cycle

• 1.Total lipids, free fatty acids, triglycerides, phospholipids and total cholesterol in blood serum, liver, brain, cardiac and skeletal muscles of Naja haje haje were determined during the different phases of the hibernation cycle.
• 2.A sharp decrease in the level of total lipids of blood serum and all tissues occurred during hibernation. Upon arousal, lipogenesis is commonly restored.
• 3.Elevated concentrations of serum free fatty acids predominated in pre-hibernation and hibernation periods, while the tissues recorded highly significant declines during hibernation.
• 4.Occurrence of marked decreases in triglycerides contents of serum and tissues except the cardiac muscles in the hibernation and arousal phases.
• 5.Sharp increases in the phospholipid contents of blood and the selected tissues were recorded during hibernation. The level declined in both liver and cardiac muscles in arousing animals.
• 6.Total cholesterol level was lowered in blood during hibernation. The cardiac muscles showed a highly significant decrease while liver, brain and skeletal muscles showed elevations in the same phase.

     

Comparative ocular blood flow

• 1.1. Blood flow values for the mammalian anterior uvea were not significantly different among species but was higher than that of the avian anterior uvea.
• 2.2. Blood flow to the primate choroid was significantly higher than that of other species.
• 3.3. The blood flow ratio which reflects the distribution of total ocular flow was significantly higher in primates than in sheep or geese.
• 4.4. The anterior ciliary artery circulation is of major importance to anterior segment blood flow in primates but not in other mammals.
• 5.5. Therefore primates are the only suitable models for ischemia following strabismus surgery.

     

Measurement of blood flow in the skin and oral mucosa of the rhesus monkey (Macaca mulatta) using laser doppler flowmetry

• 1.1. It is generally assumed that oral blood flow is higher than that of skin, and invasive methods to measure blood flow support this view.
• 2.2. However, it was not known whether this finding would be confirmed by laser Doppler flowmetry, which is a noninvasive method to measure blood flow.
• 3.3. The purpose of this study was to compare blood flow in oral and skin regions of the rhesus monkey using laser Doppler flowmetry.
• 4.4. The results demonstrated that blood flow was significantly higher in oral regions as compared to facial skin (P < 0.05).
• 5.5. This finding is most likely related to the more abundant capillary supply in oral mucosa as compared to skin.

     

Studies of the metabolic consequences of underperfusion in the isolated rat liver using a once-through perfusion technique

• 1.1. Interruption of the flow of medium to the isolated perfused rat liver results in a more reduced redox state for both the cytoplasmic and mitochondrial compartments, together with a loss of adenine nucleotides associated with a decreased content of ATP and increased concentrations of ADP and AMP.
• 2.2. Restoration of the flow reverses many of these changes.
• 3.3. The period of reperfusion is associated with increased rates of urea formation and gluconeogenesis.