bluuebunny/crossref_metadata_2025_split huggingface dataset:
The temperature dependence of the adrenergic Na+/H+ exchanger of trout erythrocytes
Authors: Cossins A. R. , Kilbey R. V. 
Published: April 2021

ABSTRACT
The effects of temperature upon the adrenergic Na+/H+ exchange of rainbow trout erythrocytes have been studied in vitro. The initial rates of H+ ejection and of increase of intracellular Na+ ([Na+1) in adrenergically stimulated cells were highly temperature-dependent, with apparent Arrhenius activation energies of 112.8±10.0 (mean±S.D., N=4) and 84.1±3.0 kJ mol−1 (N=3), respectively. The steady-state [Na+]i following stimulation decreased progressively with cooling, whilst the time required for [Na+]1 to return to control values after removal of agonist was greatly increased. The change in intracellular pH resulting from adrenergic stimulation was reduced by cooling, such that at 4°C adrenergic responses were barely measurable. The effect of temperature upon the steady state [Na+]i and pHi was probably caused by a disparity in the temperature dependence of the transport mechanisms that contribute to the respective steady states.
The Mandibular Ganglion – a new Peripheral Ganglion of the Locust
Authors: Bräunig Peter 
Published: April 2021

ABSTRACT
Paired peripheral ganglia within the locust mandibular segment are described. Each mandibular ganglion contains the cell bodies of 22–25 neurones. Four of these are sensory neurones which innervate the receptor strand of one of the mandibular proprioceptors. The other neurones connect the suboesophageal ganglion with the tritocerebral lobes of the brain, and with the first ganglion of the stomatogastric nervous system, the frontal ganglion.
External Design and Field of View of the Compound Eyes in a Raptorial Neuropteran Insect, Mantispa Styriaca
Authors: Eggenreich U. , Kral K. 
Published: April 2021

ABSTRACT
Visual fields and ommatidial angles of the compound eyes of Mantispa styriaca were determined using luminous pseudopupil and histological-anatomical techniques. The maximal horizontal overlap averaged 42.7° in females and 52.4° in males; females had only one overlap maximum, whereas males had two. In the dorsoventral direction, the binocular field had an overlap of 135.2° in the female and 142° in the male.
In light-adapted eyes, optical acceptance angles reached values of 2.0°, and they reached 3.6° with dark adaptation; interommatidial angles were between 1.8° and 2.3°. The angles were very similar over the entire eye; no acute zone was found in the frontal part of the eye, as the large binocular overlap would suggest. The results are compared with those for the praying mantis: this animal is in no way related to Mantispa but resembles it in appearance and capture behaviour.
Glucose transport in fish erythrocytes: variable cytochalasin-B-sensitive hexose transport activity in the common eel (Anguilla japonica) and transport deficiency in the paddyfield eel (Monopterus albus) and rainbow trout (Salmo gairdneri)
Authors: Tse C. M. , Young J. D. 
Published: April 2021

ABSTRACT
Erythrocytes from individual common eels (Anguilla japonica Temminck and Schlegel) exhibited widely variable initial rates of cytochalasin-B-sensitive 3-O-methyl-D-glucose (3-OMG) zero-trans influx, in the range 0–19·5 mmol 1-cells−h−1 (5mmoll−1 extracellular concentration at 20°C, 50 animals tested). Storage of cells at 4°C in a glucose-containing medium for up to 72 h had no effect on 3-OMG uptake, and there was no correlation between the sugar permeabilities of erythrocytes from different fish and intracellular ATP levels. Adrenaline and noradrenaline increased cytochalasin-B-sensitive 3-OMG transport activity; half-maximal stimulation occurred at catecholamine concentrations in the region of 1 μmol 1−1. This catecholamine-induced stimulation of sugar transport appeared to be independent of the basal cytochalasin-B-sensitive 3-OMG permeability of the cells. Kinetically, catecholamines increased the Vm of transport without changing the apparent Km (approx. 1·4 mmol 1−1). Saturable 3-OMG influx was inhibited by phloretin, D-glucose, D-deoxyglucose and D-galactose, but not by D-fructose and L-glucose. Transporter stereoselectivity was confirmed by direct measurements of D-and L-glucose uptake. Erythrocytes from two other fish species, Monopterus albus Richardson (paddyfield eel) and Salmo gairdneri Richardson (rainbow trout), unlike those from the common eel, were uniformly deficient with respect to cytochalasin-B-sensitive 3-OMG and D-glucose transport activity. Catecholamines had no effect on sugar uptake in these species.
Spinal Neuronal activity During the Pectoral Fin Reflex of the Dogfish: Pathways For Reflex Generation and Cerebellar Control
Authors: Paul D. H. , Roberts B. L. 
Published: April 2021

ABSTRACT
Single units were recorded from the spinal cord of decerebrate dogfish (Scyliorhinus canicula) during pectoral fin reflexes (PFR) evoked by electrical pulse trains to the fin. The units were classified as primary afferent neurones, motoneurones or interneurones. Motoneurones discharged for limited (and various) periods during the reflex at latencies of 20 ms or more. There was no evidence for monosynaptic activation by primary afferents. Short-latency (S) units received monosynaptic input from fast-conducting afferents at latencies (&lt;20 ms) appropriate for pre-motor interneurones. However, excitation of individual S-units by intracellular current injection never evoked motoneurone discharges, suggesting that convergence is necessary for motoneurone activation. Intracellular recordings from S-units which discharged for periods longer than the duration of the afferent volley generated by the fin stimulus showed that they receive other inputs in addition to those from primary afferent fibres. Intermediate-latency (I) units had similar properties to S-units except for a longer latency (&gt;30ms), which ruled out monosynaptic excitation by fast-conducting afferents. Antidromic activation of S-and I-units by high spinal stimulation was rarely seen and orthodromic driving was also uncommon. A significant number of interneurones with latencies greater than 60 ms (L-units) were antidromically activated by high spinal stimulation. Their discharges were often long-lasting (&gt;1 s) and we suggest that they may provide input to the cerebellum during the PFR.
The effect of varying water Ph on the acidification of expired water in rainbow trout
Authors: Lin Hong , Randall D. J. 
Published: April 2021

ABSTRACT
Acidification of expired water was studied in rainbow trout exposed to water of pH9.91, 6.80 (control) and 3.88. For the high-pH and the control exposures, the water flowing over the gills was acidified because of the dominant effect of CO2 hydration. During the low-pH treatment, the water was alkalized because of ammonium ion formation and perhaps bicarbonate dehydration. Carbon dioxide excretion was not significantly affected by the high-pH and low-pH treatments but ammonia accumulated in the plasma in both cases.
Modulation of tension production by octopamine in the metathoracic dorsal longitudinal muscle of the cricket Teleogryllus Oceanicus
Authors: O’Gara Bruce A. , Drewes Charles D. 
Published: April 2021

ABSTRACT
Application of octopamine to the metathoracic dorsal longitudinal muscle (DLM) of the cricket Teleogryllus oceanicus produced dose-dependent increases of twitch amplitude, contraction rate and relaxation rate. The threshold for octopamine effects was between 10−8 and 10−7mol l−1, while maximal effects were seen at approximately 10−5 mol l−1. The octopamine receptors were classified as octopamine2 receptors on the basis of the differential responsiveness of the muscle to the octopamine agonists naphazoline, tolazoline, clonidine and the octopamine antagonists metoclopramide and chlorpromazine. It was not possible to distinguish between octopamine2A or octopamine2B receptors in this preparation. Octopamine had both presynaptic and postsynaptic effects, since it increased both miniature end-plate potential (mEPP) frequency and muscle relaxation rate. Ata calcium concentration of 11 mmol l−1, octopamine did not affect muscle membrane potential, input resistance or EJP amplitude, but the EJP duration at half amplitude (T1/2) was slightly increased. In low-calcium saline (1.8 mmol l−1), octopamine did not affect membrane potential or T1/2, but EJP amplitude was increased. Stimulation of the octopaminergic dorsal unpaired median neuron (DUMDL), which innervates the metathoracic DLM, increased twitch amplitude in about 25% of the preparations. Failure in the other preparations was apparently due to spike conduction failure within the metathoracic ganglion. These results show that octopamine can be an important modulator of metathoracic DLM tension production.
Ultrasound-induced yaw movements in the flying Australian field cricket (Teleogryllus oceanicus)
Authors: May M. L. , Hoy R. R. 
Published: April 2021

ABSTRACT
An ultrasonic stimulus induced negative phonotactic steering in the yaw axis of tethered, flying Australian field crickets. The forewings, hindwings and twisting of the thorax generated the forces which induced the yaw turn. However, abdominal ruddering did not contribute to yaw turns. Each aspect of the yaw steering response depended upon the stimulus intensity. At higher ultrasonic intensities, the magnitude and average angular velocity increased while the latency of the yaw turn decreased. Each of these factors varied in a graded manner, revealing that this behavior is more complex than a simple reflex.
Octopaminergic modulation of the forewing stretch receptor in the locust Locusta Migratoria
Authors: Ramirez Jan-Marino , Orchard Ian 
Published: April 2021

ABSTRACT
Modulatory actions of various biogenic amines and peptides on the locust forewing stretch receptor (SR) were examined. The response of the SR to sinusoidal wing movements was unaffected by physiological concentrations (5×10−8mol l−1) of the peptides AKHI, AKHII, proctolin and FMRFamide. The biogenic amine octopamine, however, enhanced the SR response in a dosedependent manner when injected into the haemolymph of an almost intact animal or perfused over an isolated thorax preparation in which head, abdomen, gut and the entire central nervous system were removed (threshold at 5×10−8mol l−1, maximal effect at 5×10−4mol l−1 DL-octopamine). The SR was as sensitive to D-octopamine, the naturally occurring isomer of octopamine, as it was to DL-octopamine. Serotonin was equal to octopamine in effectiveness, followed in order of potency by synephrine, metanephrine and tyramine. Dopamine was ineffective. Phentolamine, but not DL-propranolol, antagonized the action of octopamine. The threshold of the modulatory effect of octopamine on the SR suggests that the increased haemolymph octopamine level which occurs during flight is sufficient to increase the SR activity. Two observations suggest that dorsal unpaired median (DUM) cells are involved in the octopaminergic modulation of the SR during flight: (1) selective stimulation of these cells modulated the SR response and this effect was blocked by phentolamine; and (2) a number of DUM cells were activated during flight. These results suggest that the SR activity is enhanced by octopamine following the onset of flight. Since the SR is involved in the control of wing beat frequency, the modulation of the SR might influence the generation of the motor pattern in flying locusts.
Sodium ion uptake by perfused gills of the blue crab Callinectes Sapidus; effects of ouabain and amiloride
Authors: Burnett Louis E. , Towle David W. 
Published: April 2021

ABSTRACT
Sodium ion uptake in the isolated perfused posterior gill of the blue crab, Callinectes sapidus Rathbun, acclimated to 5‰ salinity and 20°C was measured using 22Na as a tracer. Unidirectional influxes across individual gills occurred against large sodium concentration differences (internal perfusate=273 mmol l−1; external perfusate=l–80 mmol l−1) and depended strongly on the concentration of sodium ions present in the external perfusate. The maximum rate of influx was 3.24 μmol g−1 min−1 and the Km for this process was 23.0 mmol l−1. Ouabain added to the internal perfusate reduced the influx to an average of 51.3 % of the control values and had its maximal effect at 1 mmol l−1. Ouabain (1 mmol l−1) added to the external perfusate had no significant effect on sodium influx. Amiloride (0.1 mmol l−1) added to the external perfusate reduced the influx to an average of 38.9 % of the control values. During all treatments, perfusion pressures showed no treatment-dependent effects, indicating that the observed changes in fluxes were due to specific effects of the treatment on the epithelium and not due to some indirect effect on perfusion pattern within the gill. Treatment of the gill with the metabolic poisons cyanide and iodoacetate resulted in a rapid decline of sodium influx to 20–30% of the control values. This was correlated with a large reduction in gill ATP content to 13% of the control. The overall results of this study are consistent with the general picture of epithelial sodium uptake across gills, supporting the existence of a ouabain-sensitive Na+ pump on the basolateral membrane and an amiloride-sensitive Na+/H+ exchanger on the apical membrane.
Calcium utilization in contractures induced by acetylcholine or high-potassium saline in molluscan proboscis muscles
Authors: Brooks D. D. , Huddart H. , Lennard R. , Hill R. B. 
Published: April 2021

ABSTRACT
The mechanisms by which high-K+ saline and acetylcholine (ACh) mobilize cellular calcium in molluscan muscle was studied in three proboscis muscles of Busycon canaliculatum. BAY K 8644, a calcium agonist, enhanced tonic force induced by exposure to 25 mmol l−1 K+ in the odontophore and radular retractor muscles but inhibited this response in the radular sac muscle. Its effect on the radular protractor muscle was concentration-dependent, excitatory at 10−7 mol l−1 and inhibitory at higher concentrations. The tonic response to 80 mmol l−1 K+ was enhanced by BAY K 8644 in the odontophore retractor and radular retractor muscles but inhibited in the radular sac muscle. In all muscles, BAY K 8644 eliminated the fast twitches induced by 80 mmol l−1 K+, and inhibited the tonic ACh responses. Sucrose-gap studies with the radular protractor muscle showed that the effects of BAY K 8644 on the depolarizations induced by K+ and ACh were similar. The effect on the ACh-induced depolarization suggested that this agent had inhibited sodium influx through the ACh receptor.
Mytelase enhanced ACh-induced tonic force, but at 10−4mol l−1 it inhibited the response to doses of ACh above 10−5mol l−1. Mytolon reduced the maximum ACh-induced tonic force and increased the response threshold to ACh. ACh and high-K+ depolarization pathways were not synergistic for force development.
The existence of two separate cellular calcium pools, independently released by high-K+ saline and ACh, seems improbable. We suggest that K+ and ACh act via separate mechanisms to release calcium from a single cellular calcium pool.
Intermittent gliding flight in the pipistrelle bat (Pipistrellus Pipistrellus) (Chiroptera: Vespertilionidae)
Authors: Thomas Adrian L. R. , Jones Gareth , Rayner Jeremy M. V. , Hughes Patricia M. 
Published: April 2021

ABSTRACT
The pipistrelle bat Pipistrellus pipistrellus intersperses wingbeats in flapping flights with brief (0.1–0.3 s) glides. This undulating intermittent flight mode probably saves energy in flight. In large flight cages, captive pipistrelles glided for approximately 13.4 % of flight time, but glides were steep, and the bat accelerated during the glides. The bats sometimes glided during turns. During the glides the bat may have been unable to emit echolocation pulses and, if so, this would explain occasional wide interpulse intervals in wild pipistrelles. The steepness of the glides may be a means of improving undulating flight performance, and may also be unavoidable owing to the very small size and relatively small wings of pipistrelles.
Body drag, feather drag and interference drag of the mounting strut in a peregrine falcon, Falco Peregrinus
Authors: Tucker Vance A. 
Published: April 2021

ABSTRACT
The mean, minimum drag coefficients (CD,B) of a frozen, wingless peregrine falcon body and a smooth-surfaced model of the body were 0.24 and 0.14, respectively, at air speeds between 10.0 and 14.5 ms−1. These values were measured with a drag balance in a wind tunnel, and use the maximum crosssectional area of the body as a reference area. The difference between the values indicates the effect of the feathers on body drag. Both values for CD,B are lower than those predicted from most other studies of avian body drag, which yield estimates of CD,B up to 0.41. Several factors must be controlled to measure minimum drag on a frozen body. These include the condition of the feathers, the angle of the head and tail relative to the direction of air flow, and the interference drag generated by the drag balance and the strut on which the body is mounted. This study describes techniques for measuring the interference drag generated by (a) the drag balance and mounting strut together and (b) the mounting strut alone. Corrections for interference drag may reduce the apparent body drag by more than 20 %. A gliding Harris’ hawk (Parabuteo unicinctus), which has a body similar to that of the falcon in size and proportions, has an estimated body drag coefficient of 0.18. This value can be used to compute the profile drag coefficients of Harris’ hawk wings when combined with data for this species in the adjoining paper (Tucker and Heine, 1990).
Effects of operating frequency and temperature on mechanical power output from moth flight muscle
Authors: Stevenson R. D. , Josephson Robert K. 
Published: April 2021

ABSTRACT
Mechanical work output was determined for an indirect flight muscle, the first dorsoventral, of the tobacco hawkmoth Manduca sexta. Work output per cycle was calculated from the area of force-position loops obtained during phasic electrical stimulation (1 stimulus cycle−1) and imposed sinusoidal length change. There was an optimal stimulus phase and an optimal length change (strain) that maximized work output (loop area) at constant cycle frequency and temperature. When cycle frequency was increased at constant temperature, work output first increased and then decreased. It was always possible to find a frequency that maximized work output. There also always existed a higher frequency (termed the ‘optimal’ frequency in this paper) that maximized the mechanical power output, which is the product of the cycle frequency (s−1) and the work per cycle (J). As temperature increased from 20 to 40 °C, the mean maximum power output increased from about 20 to about 90 W kg−1 of muscle (Q10=2.09). There was a corresponding increase in optimal frequency from 12.7 to 28.3 Hz, in the work per cycle at optimal frequency from 1.6 to 3.2 J kg−1 muscle and in mean optimal strain from 5.9 to 7.9 %. Two electrical stimuli per cycle cannot increase power output at flight frequencies, but if frequency is reduced then power output can be increased with multiple stimulation. Comparison of mechanical power output from muscle and published values of energy expenditure during free hovering flight of Manduca suggests that mechanical efficiency is about 10 %. In the tobacco hawkmoth there is a good correspondence between, on the one hand, the conditions of temperature (35–40°C) and cycle frequency (28–32 Hz) that produce maximal mechanical power output in the muscle preparation and, on the other hand, the thoracic temperature (35–42°C) and wing beat frequency (24–32 Hz) observed during hovering flight.
Unitary K+ currents in growth cones and perikaryon of identified Helix Neurones in Culture
Authors: Green K. A. , Powell B. , Cottrell G. A. 
Published: April 2021

ABSTRACT
Unitary potassium (K+) currents of several different conductances have been recorded from the growth cones of isolated Cl neurones from Helix aspersa. The isolated neurones were maintained in culture for up to 1 week. Similar unitary currents were recorded in the growth cones of other isolated Helix neurones. The activity of one type of unitary K+ current recorded from the growth cones of the Cl neurone and other neurones was very similar to that described for the S-charmel of the perikarya of Aplysia sensory neurones. Another type of unitary K+ current showed fast flickering and reduced amplitude when the membrane was held at large positive potentials, which is suggestive of channel block by some agent. The conductances of the K+ channels in the growth cones of isolated Cl neurones were generally smaller than those recorded in this and in previous studies from the perikarya of Cl neurones in situ. However, unitary K+ currents recorded from the perikaryon of the Cl neurone, and from other identified neurones, in culture also had lower conductances than those recorded in situ. The mean resting potential of the isolated neurones was smaller than those from neurones in situ. This and other results suggested that reduced intracellular K+ concentration in the isolated neurones might be an important factor in deciding the conductance of the recorded channels.
The Clasping Reflex In Frogs And Toads And The Seasonal Variation In The Development Of The Brachial Musculature
Authors: Smith C. L. 
Published: April 2021

ABSTRACT
By the methods described in this paper it has been shown that:
A clasping action can be produced in male frogs at all times of the year. This reaction is peculiar to the male. The course of the decline and onset of the hypertrophy of the brachial musculature up to a maximum at the breeding period can be followed. This hypertrophy appears to follow fairly closely the changes occurring in the interstitial tissue of the testis.
Proprioception In Insects
Authors: Pringle J. W. S. 
Published: April 2021

ABSTRACT
A group of campaniform sensilla occurs on each of the joints of the maxillary palp of Periplaneta americana. Each group is supplied from a single large sensory nerve fibre. Impulses in the nerves from the sensilla can be recorded at the base of the maxilla. Adaptation is slow and incomplete. The sensilla respond to passive straight or sideways bending of the joint, and also strongly to pressure on the cuticle. They are excited only to a lesser extent when the segment is moved actively by its own muscle. It is shown that the observations are consistent with the view that the campaniform sensilla are “stress receptors” responding to strains in the cuticular skeleton. Their action as proprioceptors is compared with that of the vertebrate tension receptor.