Mechanical properties of locust extensor tibiae muscles

• 1.1. The prothoracic and mesothoracic extensor tibiae muscles of the locust respond to activity in the “slow” extensor tibiae motoneuron (SETi) with very slow contractions and a low fusion frequency, while their phasic contractions are more rapid than those of the metathoracic extensor tibiae muscle.
• 2.2. SETi activity can induce a memory or “catch” effect in which a high tension is maintained by a lower frequency than is needed to develop it. “Catch” tension is reduced by phasic contractions of the muscle or by activity in the inhibitory axon.
• 3.3. A bundle of tonic fibres isolated from the metathoracic extensor tibiae muscle exhibits co-ordinated rhythmic contractions similar to those recorded from intact muscles.
• 4.4. Depolarizations of the tonic fibres coincide with the contractions and are sometimes accompanied by bursts of EPSPs and IPSPs.
• 5.5. The tonic fibres are electrically-coupled.

     

Enzyme activities and isozyme composition of triglyceride,diglyceride and monoglyceride lipases in Periplaneta americana,Locusta migratoria and Polia adjuncta

• 1.1. Measurements of maximal enzyme activities were combined with an electrophoretic study of isozyme make-up in an examination of triglyceride, diglyceride and monoglyceride lipases from the flight muscle, fat body and gut of the cockroach, Periplaneta americana and the locust, Locusta migratoria and from the flight muscle and fat body of the moth, Polia adjuncta.
• 2.2. Tri-, di- and mono-glyceride lipases were present in all tissues of the insects with diglyceride lipase ≥ triglyceride lipase activity in all cases and monoglyceride lipase ≥ diglyceride lipase activity in locust and moth.
• 3.3. In the flight muscle, a strong correlation was found between the activities of lipases and the known use of lipid as a fuel for flight in these insects. Lipase activities were lowest in the cockroach (a carbohydrate-based flight metabolism), intermediate in the locust (both carbohydrate and lipid-fueled flight), and highest in the moth (a non-feeding, lipid-catabolizing adult) flight muscle.
• 4.4. Polyacrylamide gel electrophoresis, using substrate-impregnated gels and stained for fatty acids released by lipase action, demonstrated the presence of tissue specific isozymes of tri-, di- and mono-glyceride lipases in the three insects. In addition, some, but not all, tissues showed multiple molecular forms of one or more of the lipases.
• 5.5. Diglyceride and monoglyceride lipase activities in both flight muscle and fat body of the insects coelectrophoresed suggesting the possibility that these two lipase activities might be catalyzed by a single enzyme protein.

     

Descending stridulatory interneurons in the suboesophageal ganglion of two grasshopper species

1. The activity of interneurons in the suboesophageal ganglion of the acridid grasshoppers Omocestus viridulus (L.) and Chorthippus mollis (Charp.), recorded intracellularly during stridulation, was found to conform to the rhythm of the singing movements. The arborizations of these neurons in this ganglion are largely bilaterally symmetrical; the axon descends contralaterally to the soma and passes at least into the metathoracic ganglion.
2. The anatomical and physiological characteristics of these neurons are similar in the two species and of four types. Three of them exhibit a tonic, spontaneous activity in the resting animal, which is modulated in the stridulatory rhythm as soon as singing begins. The fourth type has no resting activity and discharges only during the song, in a stridulation-specific pattern.
3. By transecting the connectives it was shown that the rhythmic activity of the neurons is not determined by input from the brain, nor is it generated in the suboesophageal ganglion itself. It is based on information about the song pattern that ascends from the thoracic ganglia.

     

Axonal pathways of giant neurons identified in the right parietal and visceral ganglia in the suboesophageal ganglia of an African giant snail (Achatina fulica Férussac)

• 1.1. The axonal pathways of thirteen giant neurons identified in the right parietal and the visceral ganglia, found in the suboesophageal ganglia of an African giant snail (Achatina fulica Férussac), were investigated by intracellular injections of Lucifer Yellow, with regard to their axonal projections into the following six peripheral nerves: lap n (left anterior palliai nerve), lpp n (left posterior palliai nerve), int n (intestinal nerve), anal n (anal nerve), rpp n (right posterior palliai nerve) and rap n (right anterior palliai nerve).
• 2.2. These projections were confirmed by the recording of the axonal responses from the nerves.
• 3.3. On the dorsal surface of the right parietal ganglion, the following four giant neurons were identified: PON (periodically oscillating neuron), TAN (tonically autoactive neuron), RAPN (right anterior palliai neuron), and d-RPLN (dorsal-right parietal large neuron).
• 4.4. The PON axonal pathways projected into int n; those of TAN into all of the nerves examined; those of RAPN into lap n, lpp n, int n, anal n and rap n.; and those of d-RPLN into pd nn (pedal nerves) through the pedal ganglia, lpp n, anal n, rap n and sometimes lap n.
• 5.5. On the dorsal surface of the visceral ganglion, the following four giant neurons were also identified: VIN (visceral intermittently firing neuron), FAN (frequently autoactive neuron), INN (intestinal nerve neuron) and d-VLN (dorsal-visceral large neuron).
• 6.6. The VIN axonal pathways, which had no branch into the six nerves examined, went to both the right and the left pedal ganglia, sending a branch into the cerebro-pleural connective; those of FAN projected into lap n, anal n and rap n, and sometimes into lpp n and rpp n; those of INN into int n; and those of d-VLN into pd nn, lap n, lpp n, anal n and rap n.
• 7.7. On the ventral surface of the right parietal ganglion, v-RPLN (ventral-right parietal large neuron) was identified. The axonal pathways went to pd nn, lap n, lpp n, anal n and rap n.
• 8.8. On the ventral surface of the visceral ganglion, the four giant neurons, v-VNAN (ventral-visceral noisy autoactive neuron), v-VLN (ventral-visceral large neuron), r-VMN (right-visceral multiple spike neuron) and 1-VMN (left-visceral multiple spike neuron) were identified.
• 9.9. The axonal pathway of v-VNAN projected into rpp n and rap n; those of v-VLN into pd nn, lap n, anal n, rap n and sometimes to lpp n; those of r-VMN into int n and rpp n; and those of 1-VMN also into int n and rpp n.
• 10.10. The present morphologial investigations of the giant neurons confirmed well the identifications of the neurons previously studied. The axon of the neurons examined here, except for VIN, projected into some of the peripheral nerves, while the VIN axon extended into the cerebro-pleural connective.
• 11.11. The five neurons, PON, TAN, v-VNAN, r-VMN and 1-VMN, formed fine axonal arborizations terminating at the neuropile, while the arborizations of the other neurons were not clearly observed.
• 12.12. Although the anatomical structures of the portion examined of the suboesophageal ganglia are asymmetrical, three pairs of symmetrically-situated neurons, d-RPLN and d-VLN, v-RPLN and v-VLN, and r-VMN and 1-VMN, were found, indicating the existence of symmetrical components in the ganglia.

     

Creatine kinase from the electric organ of Electrophorus electricus (L.)—isozyme analysis

• 1.1. Creatine kinase (CPK) isozymes of extracts from the electric organ, dorsal muscle and brain of Electrophorus electricus (L.) were analysed with Cellogel electrophoresis. A single component corresponding to the MB-form was obtained for both electric organ and the dorsal muscle. The BB-form was present in the brain extract.
• 2.2. Upon acetone fractionation of the aqueous extract of electric organ, the final fraction was submitted to gel filtration and presented a single peak of CPK activity.
• 3.3. Characterization of this fraction by thin-layer gel filtration indicated an apparent molecular weight of 80,000 which corresponds to the enzyme dimeric structure.
• 4.4. The implications of this finding with the muscular origin of the electric organ are discussed.

     

Topography and distribution of motor neurons supplying uropod muscles of a crayfish

• 1.1. The pathway and distribution of motor neurons in the uropod muscles of the crayfish, Procambarus clarkii, was investigated electrophysiologically and histologically.
• 2.2. There were three crossing points of motor neurons between the peripheral motor bundle originating from the second and third roots of the sixth abdominal ganglion.
• 3.3. It seems that there are no anatomical and functional regularity in the innervation pattern of the uropod muscles.

     

Two kinds of peripheral afferent neurons in the earthworm reflex arc

• 1.1. Two kinds of neurons were identified in the body-wall longitudinal muscle layer of the earthworm, Amynthas hawayanus, by the simultaneous potential recording and Lucifer Yellow-CH injection method with a single microelectrode.
• 2.2. Both kinds of neurons have their somata, neuntes and longitudinal processes imbedded in the longitudinal muscle layer. Those with two circular processes extending into the third segmental nerve trunk are tentatively named “intra-nerve-trunk” neurons and those with four circular processes extending into four setae shafts are tentatively named “intramural” neurons.
• 3.3. Both kinds of neurons responded to electrical and mechanical stimuli applied in an afferent direction to them.
• 4.4. The “intra-nerve-trunk” neuron decreased its response amplitudes to these stimuli after the third nerve trunk was sectioned in correlation to the response amplitude decrease recorded from the nerve trunk after it was sectioned.
• 5.5. The response amplitude decrease due to denervation implies a nonlinear structure of the earthworm reflex circuits.
• 6.6. The “intramural” neurons are believed to be primary sensory neurons connected to the mechanoreceptors in the setae.

     

Programmed loss of flight ability in the early adult life of the blowfly Phormia terrae novae as a possible mechanism of intraspecific niche building with respect to the duration of life

• 1.1. The age related flight performance of males and females of the blowfly Phormia terrae novae was studied and the influence of artificially fed glucose determined.
• 2.2. Maximum flight ability—measured as flight distance, duration and initial velocity—was achieved during the first week after emergence, thereafter the flight performance drops precipitously between the 12th and 17th day of adult life.
• 3.3. Males and females, fed and unfed individuals, show no difference in their time course of flight ability.
• 4.4. The possible causes of the programmed loss of flight performance were discussed with regard to histological and enzyme activity changes observed at the same and other species.
• 5.5. The biological significance of this physiological age effect was revealed.

     

Neural network regulating heart activity in Aplysia depilans and its comparison with other gastropod species

• 1.1. The efferent part of heart regulatory neural network was investigated in Aptysia depilans.
• 2.2. In the abdominal ganglion 9 identified giant neurons and 12 unidentified small cells were found which modified heart activity, 3 neurons of the RP1G. 1-1 cell of the RPG and LPG involved in heart regulation were also detected.
• 3.3. Similar to other gastropod species, the heart regulatory neural network of Aplysia depilans is scattered throughout the CNS.
• 4.4. Most of the neurons having efferent influences on the heart receive also inputs from heart. There were only six exceptions, five located in the abdominal ganglion and one in the LPG. A left side dominancy was found in the localization of heart regulatory neurons.
• 5.5. One interneurone (L10) and two motoneurons (RB_HE, LD_HI1) were identified and described earlier in other Aplysia species. Cell L10 was silent or displayed tonically active or a bursting pattern. Its tonic firing led to the inhibition of the heart. Neurone L10 received indirect information from the heart.
• 6.6. There exist mutual connections between or similar inputs in neurones located in different ganglia. The regulation of heart activity in Aplysia depilans seems to be accomplished by the aid of multifunctional neural networks, where the regulation of various organs is subordinated to the need of the whole organism.

     

Feeding and a serotonergic interneuron activate an identified autoactive salivary neuron in Limax maximus

• 1.1. A single neuron is found in each buccal ganglion of the giant garden slug, Limax maximus, which is autoactive and has an axon in both the ipsilateral and contralateral salivary nerve.
• 2.2. This neuron, the bilateral salivary neuron (BSN), is a slow bursting neuron and is presynaptic to some of the secretory acinar cells of the salivary gland.
• 3.3. Increases in BSN action potential frequency and saliva flow during the generation of feeding motor program are shown, as is the relationship of BSN activity to that of other salivary neurons.
• 4.4. BSN is affected synaptically by the serotonergic metacerebral giant cell.

     

Sex differences in vascular reactivity to adrenergic agents in the rat

• 1.1.The study was designed to determine if there are sex-dependent differences in vascular reactivity to adrenergic agents.
• 2.2.Vascular reactivity of both aortic and tail artery smooth muscle from male and female rats to various vasoactive agents was assessed. 3.li]The vascular response of aortic smooth muscle to both phenylephrine and isoproterenol were significantly greater in male rats as compared to females.
• 3.4.There were apparent sex differences in responsiveness to the KCl-induced, non-receptor mediated contraction of aortic smooth muscle in that the sensitivity to KCl was enhanced in male rats.
• 4.5.No sex differences were observed in tail artery preparations.
• 5.6.Phentolamine reduced the maximal tension induced by KCl in the tail artery but not aortic artery preparations. This effect was not sex dependent.
• 6.7.No differences in the vascular smooth muscle responsiveness to acetylcholine or sodium nitrate was observed between groups or within different vascular beds.
• 7.8.The increased sensitivity of males to adrenergic challenge could explain in part some of the existing sex differences in cardiovascular disease and hypertension.

     

Purification and some properties of isocitrate dehydrogenase of a blowfly Aldrichina grahami

• 1.1. NADH-dependent isocitrate dehydrogenase has been purified 110-fold from the crude extract of the flight muscle mitochondria of Aldrichina grahami.
• 2.2. The purification procedure involved Triton X-100 treatment of isolated mitochondria, column chromatography on DEAE-cellulose, Affi-gel blue, and P-cellulose.
• 3.3. The purified enzyme was homogeneous by criteria of the polyacrylamide gel electrophoresis.
• 4.4. The enzyme of the blowfly contains more acidic amino acids and less hydrophobic amino acids than that of pig heart.
• 5.5. The molecular weight was determined to be 330,000 daltons. The subunit construction differs from ghat of mammalian isocitrate dehydrogenase.

     

Rat hypothalamic noradrenaline levels following midbrain raphé nuclei lesions

• 1.1. Electrolytic lesions of the median and dorsal raphé nuclei resulted in statistically significant reductions in rat hypothalamic noradrenaline which were observed 1 or 2 days after lesioning, while no changes were observed 7 or 14 days after lesioning.
• 2.2. The short term (1–2 days) raphé nuclei lesions produced no changes in hypothalamic 5-hydroxytryptamine or a small reduction in 5-hydroxyindole acetic acid while the expected marked reductions were observed after 7 days.
• 3.3. The reduction in hypothalamic noradrenaline observed after short term raphé nuclei lesions suggests the existence of a positive feedback loop between 5-hydroxytryptamine neurons and noradrenaline terminals in the hypothalamus.

     

An electrophysiological study of the topographical organization of the multisensory torus semicircularis of the rainbow trout

• 1.1. The recorcling sites of 68 acoustical (A), 86 visual (V) sensitive units and 36 bimodal units, predominantly encountered within the torus semicircularis, have been examined with respect to their response characteristics.
• 2.2. Bimodal units are located more rostrally than A units, but no topographic preference has been found for the V units. The response signs of the three modality types (excitatory, inhibitory for the A modality; On, Off for the V modality) also show no topographic organization.
• 3.3. The spontaneous spike rate of the V type is smaller than that of the A and bimodal type. Many bimodal cells showed spontaneous activity (76%). Non-spontaneous units are more numerous in the rostral torus.
• 4.4. The frequency sensitivity of the A units can be divided into H (high frequency) and B (broadband) units.
• 5.5. B units, which frequently show a more complex excitatory-inhibitory behaviour are located in the middle and caudal part, whereas the H units are mainly found in the rostral part of the torus.
• 6.6. Phase-locking is restricted to spontaneous, monomodal B units.
• 7.7. Clusters of neurons can be found in the torus, which contain either A or V units. In the dorso-ventral direction the A clusters are about half the size of the V clusters.

     

Calcium binding by sarcoplasmic reticulum and mitochondria isolated from an annelid visceral muscle in relation to whole muscle calcium influx and efflux

• 1.1. Nereis pharangeal visceral muscle is composed of obliquely striated fibres with low mitochondrial density and moderately developed sarcoplasmic reticulum.
• 2.2. Isolated mitochondria and sarcoplasmic reticulum showed moderate passive calcium binding but only low ATP-promoted calcium binding which was inhibited by caffeine.
• 3.3. Whole fibres preloaded with Ca⁴⁵ showed a two compartment efflux. The slow, presumably intracellular, compartment accounted for only 10% of total Ca⁴⁵ activity.
• 4.4. Both acetylcholine and high KCl treatments stimulated calcium influx, causing contractures while calcium-free and EGTA treatments inhibited both these contractures and normal spontaneous contractions.
• 5.5. Lanthanum inhibited normal contractility and KCl contractures. Lanthanum also inhibited Ca⁴⁵ influx but was without effect on Ca⁴⁵ efflux.
• 6.6. It is concluded that there is little calcium storage capacity in these visceral muscle fibres and that normal contractions are strongly dependent upon extracellular calcium influx.

     

Bioassay and proteolytic activity of digestive enzymes from octopus saliva

• 1.1. A bioassay for octopus saliva, based on detachment of crab dactylopodite flexor muscle under standard conditions, has been developed.
• 2.2. There is a direct relationship between increasing caseinolytic activity of saliva from Eledone cirrhosa and decreasing muscle detachment time.
• 3.3. Fractionation of saliva, using preparative isoelectric focusing, shows that muscle releasing activity is restricted to fractions containing proteins with high isoelectric points and maximum caseinase activity.
• 4.4. It is concluded that proteolytic enzyme(s) in octopus saliva selectively release crab muscle from attachment to the carapace.

     

The optic nerve mediates the circadian pigment migration in the median eyes of the scorpion

• 1.1. The peripheral visual pathway from the median eyes of the scorpion Androctonus australis was interrupted at different points and the effect on the circadian rhythm of median-eye sensitivity was examined.
• 2.2. Any interruption of the visual pathway distal to the supraesophageal ganglion abolishes the circadian sensitivity rhythm in the median eyes. This rhythm is thus controlled by efferents in the optic nerve (very probably via the neurosecretory axons) rather than by way of the hemolymph.
• 3.3. Following transection of the optic nerve, the sensitivity of the median eyes proceeds rapidly to the daytime state. This condition is associated with movement of the screening pigment into the distal ends of the visual cells.
• 4.4. The oscillator system controlling the circadian pigment migration in the median eye cannot be located in the eye itself, but must lie in the CNS, proximal to the first optic ganglion. The oscillator itself need not be connected to both median eyes in order to function normally, as revealed by the continued rhythm in the contralateral eye following unilateral optic nerve section.

     

Flight effects on certain blood parameters in homing pigeons Columba livia

• 1.1. Various blood parameters were monitored in resting and flown homing pigeons. A homing flight of 48 km lasting 60–80 min did not significantly alter plasma levels of total protein, electrolytes and plasma osmolality, which indicated maintenance of the homeostatic stability of the internal milieu during moderate exercise.
• 2.2. Plasma concentrations of marker enzymes such as alanine aminotransferase (ALAT), aspartate aminotransferase (ASAT), laetate dehydrogenase (LDH) and creatine phosphokinase (CPK) that tend to denote muscle damage and metabolic flux in prolonged exercise, were also not altered, thereby indicating the steady state of tissue structure and function during a flight of this magnitude.
• 3.3. Significant increases in plasma levels of uric acid and creatinine and decreases in plasma albumin were observed in the flown pigeons.
• 4.4. The flight-induced increase in blood uric acid could be attributed to increased purine catabolism and the increase in creatinine to increased nucleotide turnover.
• 5.5. It is suggested that the higher uric acid levels should not only enhance water conservation, but may also reduce flight-induced hyperthermia besides acting as an antioxidant defence against oxidative tissue injury.
• 6.6. The rise in creatinine is indicative of the breakdown of phosphocreatine for energy during the initial period of flight prior to the utilization of carbohydrate and lipid as fuels.
• 7.7. The decrease in plasma albumin should account for the albumin as lipid carrier lost in transport to the muscles during flight.

     

Physical conditioning: Effect on the myoglobin concentration in skeletal and cardiac muscle of bar-headed geese

• 1.1. A 12 week program of treadmill exercise (0.7 m/sec, 30 min per day, five days per week), significantly increased the myoglobin concentration of the femorotibialis medius muscle in bar-headed geese as compared to nonexercised controls.
• 2.2. The myoglobin concentration differed among various muscles within a bird. The highest myoglobin concentrations were found in the primary flight muscle, the pectoralis major, and in cardiac muscle.
• 3.3. By physically conditioning their muscles, bar-headed geese may improve the oxygen flow to mitochondria and, thereby, enhance their ability to exercise under conditions of low oxygen partial pressures.

     

Glycogen phosphorylase in lobster hepatopancreas: action of proteases on the enzyme

• 1.1. In lobster hepatopancreas, extracellular protreases cause the inactivation of glycogen phosphorylase.
• 2.2. The proteolysis of glycogen phosphorylase purified from rabbit muscle by these proteases has been shown by SDS-polyacrylamide gel electrophoresis.
• 3.3. A cell isolation technique has allowed us to remove proteases of extracellular digestion and to measure glycogen phosphorylase activity in lobster hepatopancreas.
• 4.4. The glycogen phosphorylase activity seems to be mainly associated with R cells while it could not be detected in B cells.