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.

     

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.

     

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.

     

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).

     

Heart rate and its cholinergic control in the sole (Solea vulgaris), acclimatized to different temperatures

• 1.1. The effects of thermal acclimatization at 10 and 24°C on heart rate were investigated on unrestrained soles (Solea vulgaris).
• 2.2. The sensitivity of heart rate to temperature changes induced by temperature acclimatization was higher in cold-acclimatized than in warm-acclimatized soles.
• 3.3. Heart rate of cold-acclimatized fish to temperature changes was not affected by blocking the vagal tone with atropine.
• 4.4. After atropine treatment the ability of heart rate to show thermal compensation decreased in warm-acclimatized soles.
• 5.5. It is suggested that the vagus nerve can function differently at different temperatures.

     

Main kinetic characteristics of acetylcholinesterase from brain of Hypostomus punctatus,a Brazilian bentonic fish (cascudo)

• 1.1. A potentiometric method for the assay of cholinesterase has been proposed and compared with a colorimetric assay.
• 2.2. Main kinetic parameters of cholinesterase from Hypostomus punctatus brain were determined indicating that true acetylcholinesterase is by far the predominant enzyme in the brain of this fish.
• 3.3. We have compared our data with published results described from other fish species.
• 4.4. The enzyme inhibition achieved after 3 hr incubation of brain homogenates with ethyl-parathion have indicated that this enzyme shows a characteristic organophosphorous sensitive behavior.

     

Arginase,ornithine decarboxylase and S-adenosylmethionine decarboxylase in chicken brain and retina

• 1.1. Arginase, ornithine decarboxylase and S-adenosylmethionine decarboxylase are active in both retina and brain. Activity is higher in cerebellum than in the cerebral hemispheres and optical lobes.
• 2.2. Arginase and ornithine decarboxylase are very active in the retina of very young chicks, while S-adenosylmethionine decarboxylase is poorly active. By contrast, S-adenosylmethionine decarboxylase is much more active in brain.
• 3.3. The pattern of activity during development is different; only ornithine decarboxylase is very active during embryonal life; S-adenosylmethionine decarboxylase, at all events in brain, is more active in adult life.
• 4.4. Ornithine decarboxylase is inhibited in vitro by α-difluoromethylornithine, but not in vivo. Diaminopropane inhibits brain ornithine decarboxylase, but does not induce an ornithine decarboxylase-antizyme.
• 5.5. Methylglyoxal bis(guanylhydrazone) promotes an increase of S-adenosylmethionine decarboxylase activity in both the brain and the retina in vivo.

     

Bioelectric activity from isolated brain of Lacerta atlantica

• 1.1. A method of maintaining the isolated lizard brain in a Ringer solution is described.
• 2.2. Microelectrodes and EEG recordings from different areas of telecenphalon and optical tectum were made.
• 3.3. The prolonged cells survival under the experimental conditions described has been demonstrated for several hours.
• 4.4. The isolated brain of Lacerta makes it easy to reach anatomical pathways which otherwise, in the whole animal, would be more difficult to reach.

     

Catecholamines affect storage and retrieval of conditioned odour stimuli in honey bees

• 1.1. The effects of injected catecholamines and their analogues on odour learning in honey bees is described.
• 2.2. Dopamine blocks the retrieval of a learned odour signal with a specific time course and does not block the storage of this signal.
• 3.3. Noradrenaline blocks retrieval and storage of a conditioned odour signal.
• 4.4. Amphetamine shows the same effects as noradrenaline.
• 5.5. Haloperidol has no affect on memory retrieval or storage.

     

Respiration in the eastern water dragon,Physignathus lesueurii (agamidae)

• 1.1. Some aspects of the gas exchange system of a diving lizard, Physignathus lesuewii were studied.
• 2.2. Breathing patterns were analysed.
• 3.3. Breathing rate increases logarithmically with temperature and Q₁₀ = 1.8. LogBR = −0.237 + 0.0256 T.
• 4.4. Gas tensions in lung air and arterial and venous blood were measured. Arterial pH declines with increasing temperature.
• 5.5. Temperature has a marked effect on oxygen affinity of the blood (ΔH = −10.1 kcal mol⁻). A Bohr effect was also noted.
• 6.6. CO₂ equilibrium curves were drawn.
• 7.7. The results are considered with a view to anticipating the efficiency of the gas exchange system of this species under conditions of variable temperature and during diving.

     

Breast,hips, and buttocks revisited: Honest fatness for honest fitness

This paper comments on: Low, B. S., Alexander, R. D., and Noonan, K.M. Human hips, breast, and buttocks: Is fat deceptive? Ethology and Sociobiology 8: 249-247, 1987. In it I argue that:

• 1.1. Sexual selection has probably not been the most important selection pressure on
• 2.female human body shape.
• 3.2. Male humans in different cultures find different aspects of the female body attractive
• 4.and therefore are unlikely to have exerted consistent directional sexual selection on
• 5.the female body.
• 6.3. Breast size is not correlated with lactation success.
• 7.4. Visible hip width is not correlated with parturition success.
• 8.5. Women would lower their fitness if they tried to deceive men about their internal
• 9.pelvic dimensions.
• 10.6. There are many alternative hypothesis to explain the existence of fat onwomen's
• 11.breast, hips, and buttocks.

     

Renin-angiotensin system in antarctic fishes

• 1.1. The presence of a renin-angiotensin-like system has been investigated in the Antarctic fishes Chionodraco hamatus (Fam. Channichthydae) and Pagothenia (Trematomus) bernacchii (Fam. Notothenidae).
• 2.2. A renin-like activity is present in plasma and kidney of both the white blooded (Chionodraco) and the red blooded (Pagothenia) species.
• 3.3. An angiotensin converting enzyme-like activity has been demonstrated in plasma, gills and kidneys of both species. The activity is inhibited by high temperature.
• 4.4. From our data a renin-angiotensin-like system is present in the Antarctic fishes studied but the cascade of enzymes is active only at low temperatures.

     

Seasonal changes of water,electrolytes and aldosterone levels in blood serum,brain and kidney of the Egyptian cobra “Naja haje haje”

 

• 1.The levels of water, Na, K, Ca and Mg in blood serum, brain and kidney and aldosterone level in blood of Naja haje haje were studied during the different phases of the annual cycle.
• 2.The water content in the tissues studied displayed only minor changes as the animals passed from one phase to the other.
• 3.A significant increase in Na was recorded in the brain during the different phases indicating a depressed sodium pump, whereas the blood Na level showed a significant decrease during hibernation.
• 4.K increased in blood serum, brain and kidney during hibernation, while a nonsignificant decrease was found in blood serum during arousal. The brain may act as a potassium reservoir.
• 5.An increase in Ca and Mg concentration was recorded in blood serum, brain and kidney during prehibernation and hibernation. The data suggested a homeostatic function in the transport and metabolism of these cations.
• 6.Aldosterone exhibited a highly significant decrease especially during hibernation. The aldosterone regulation of ionic composition is discussed.
• 7.Na/K and Ca/Mg ratios in the brain may explain the decreased excitability during winter torpor.

     

The influence of aerial exposure on gas exchange and cardiac activity in the shore crab,Carcinus maenas (L.)

• 1.1. The cardiovascular physiology of adult Carcinus maenas (L.) emerging into air has been investigated at three different air temperatures.
• 2.2. Transition from seawater to air or vice versa triggered transient increases in cardiac and locomotor activity.
• 3.3. However, crabs became inactive 5–10 min after emerging from seawater (15°C) into air at the same temperature (15°C) or at lower temperatures (12–13°C) and heart rate fell.
• 4.4. At higher air temperatures (18–20°C) heart rate rose but to a lesser extent than predicted from aquatic Q₁₀ heart-rate values.
• 5.5. Crabs were again quiescent in aerial conditions.
• 6.6. Mean arterial oxygen tension (Pa_o2) was ~ 74 mmHg in submerged crabs but fell to ~ 38 mmHg in air while mean arterial carbon dioxide tension (Pa_o2) increased from 1 to 4 mmHg resulting in respiratory acidosis.
• 7.7. A model of gill function is proposed to explain the development of internal hypoxia in air.
• 8.8. The results are discussed in relation to the distribution of adult and juvenile C. maenas in situ.

     

Insulin,glucagon and catecholamine interactions in avian liver explants

• 1.1. A mechanical tissue chopper was used to obtain liver explants (35–75 mg) from 2- to 3-week-old chickens to determine both tissue sensitivity and metabolic effects of isoproterenol, avian insulin and glucagon.
• 2.2. Avian insulin had no effect on lipogenesis; however, lipogenesis was decreased by dibutyryl cyclic AMP. Insulin did not overcome a decrease in lipogenesis caused by catecholamines. Therefore, this control mechanisms is not modulated by insulin.
• 3.3. Preincubation in the presence of glucagon decreased in vitro lipogenesis. Preincubation in the presence of a 19–29 amino acid construct that approximated the radioimmune site for glucagon did not result in a similar effect. Therefore, this site does not relate to the biopotency of the hormone.
• 4.4. A previously noted catecholamine induced decrease in in vitro lipogenesis was verified, showing that points of in vitro regulation are under phosphorylation-dephosphorylation control.
• 5.5. Preincubation of slices (1 hr) with propranolol blocked the inhibition of lipogenesis caused by α and β adrenergic agonists (arterenol or isoproterenol) during a subsequent 2-hr incubation.
• 6.6. Preincubation of slices with either of these agonists decreased lipogenesis even following an extensive washout.
• 7.7. Inhibition could be overcome with propranolol, a β adrenergic antagonist.

     

Kinetic studies of catechol-o-methyltransferase from the brain of the African catfish,Clarias gariepinus

• 1.1. Optimum in vitro conditions, and kinetics of the enzyme catechol-O-methyltransferase from the brain of the male African catfish were studied.
• 2.2. A saturated level for S-adenosylmethionine, as methyldonor, and magnesium as cofactor was reached at 5 μM and 10 mM, respectively.
• 3.3. The addition of ascorbic acid, as an antioxidant, and tranylcypromine, as a MAO inhibitor, was not necessary, during incubations with fore-brain homogenates.
• 4.4. Kinetic analysis of the methylation of catecholestrone, catecholestradiol and dopamine showed K_m values of 1.2, 0.6 and 0.5 μM, respectively.
• 5.5. The affinity of the catecholsubstrates for the enzyme catechol-O-methyltransferase is much higher in the brain of the African catfish than in tissues of mammals.

     

A quantitative method for analysis of radiolabelled proteoglycans synthesized by cultured human arterial smooth muscle cells

• 1.1. Sulphate labelled proteoglycans (PG) synthesized by cultured human arterial smooth muscle cell have been quantified using an improved method based on a combination of specific enzymes and ethanol precipitation.
• 2.2. The present method gives quantitative data of PGs and subclasses allowing batchwise analysis of a large number of samples.
• 3.3. Approximately 81 % ± 1.7% (mean ± SD, n = 6) of total PGs synthesized by human arterial smooth muscle cells accumulated in medium.
• 4.4. In cell layer and medium chondroitin sulphate proteoglycan constituted 65.0% ± 0.3% and 75.8% ± 0.7% (mean ± SD, n = 3), respectively of sulphated PGs.
• 5.5. Heparan sulphate proteoglycan accounted for 26.8% ± 0.6% in cell layer and 22.6% ± 0.5% (mean ± SD, n = 3) in medium of sulphated PGs.

     

Physiological responses to exercise and hypoglycaemia stress in pigs of differing adrenal responsiveness

• 1.1. Twelve Large White × Landrace male pigs, six with high adrenocortical response to ACTH, and six with low response, were subjected to mild and moderate exercise, and then to insulin-induced hypoglycaemia.
• 2.2. Plasma ACTH, cortisol, catecholamines and some haematological and plasma biochemical parameters were determined in response to exercise, and glucose and cortisol in response to insulin challenge.
• 3.3. High responders had significantly greater increases than low responders in ACTH, cortisol and catecholamines following exercise, and in cortisol following insulin challenge.
• 4.4. The results suggest that differences in adrenocortical response to exogenous ACTH are an accurate reflection of the animal's response to stressful stimuli.

     

Effects of angiotensin II and bladder condition on hydration behavior and water uptake in the toad,Bufo woodhousei

• 1.1. Water absorption response (WR) behavior and water weight gain were examined in hydrated toads, Bufo woodhousei, treated with angiotensin II (All) or with a control Ringer's solution. The effects of urinary bladder condition (ad lib. bladder urine or empty bladder) were examined concurrently.
• 2.2. Toads treated with All (100μg/100g body weight), spent more time in WR posture and absorbed more water than Ringer's-injected toads.
• 3.3. Toads with empty bladders maintained WR posture for longer periods of time and gained more weight than toads whose bladders were not emptied.
• 4.4. The effects of All and bladder urine on water absorption by B. woodhousei appear to be separate and additive.