The neurophysiology of respiration in decapod crustacea. I. The motor system

1968 ◽  
Vol 46 (3) ◽  
pp. 585-596 ◽  
Author(s):  
Valerie M. Pasztor
Keyword(s):  
Action Potentials ◽  
Motor Command ◽  
Blue Staining ◽  
Fiber Types ◽  
Quiet Breathing ◽  
Inhibitory System ◽  
Decapod Crustacea ◽  
Phasic Type ◽  
Gill Ventilation ◽  
Frequency Burst

The pump responsible for gill ventilation in the crayfish is operated by 11 muscles of the second maxillae. These muscles arc described and named and their action analyzed by the recording of nerve and muscle potentials. During quiet breathing, the normal motor command to each muscle is a short, high-frequency burst of evenly spaced action potentials (7–25 spikes at average frequencies of 60–140/sec). Histological and physiological evidence shows that the muscles represent mixed populations of fiber types. Most fibers are of the "gradedly responding" phasic type. Although methylene blue staining reveals two axons to each muscle, the normal motor command arrives via one axon only. The second may be a "fast" axon operating only in exceptional circumstances. No evidence has been found of a peripheral inhibitory system.

scholarly journals Functional, cellular, and biochemical adaptations to elastase-induced emphysema in hamster medial scalene

2000 ◽  
Vol 88 (4) ◽  
pp. 1327-1337 ◽  
Author(s):  
Mario Fournier ◽  
Michael I. Lewis
Keyword(s):  
Heavy Chain ◽  
Fatigue Properties ◽  
Emg Activity ◽  
Dynamic Hyperinflation ◽  
Fiber Types ◽  
Quiet Breathing ◽  
Cross Sectional ◽  
Sds Page ◽  
Inspiratory Activity

The scalene has been reported to be an accessory inspiratory muscle in the hamster. We hypothesize that with the chronic loads and/or dynamic hyperinflation associated with emphysema (Emp), the scalene will be actively recruited, resulting in functional, cellular, and biochemical adaptations. Emp was induced in adult hamsters. Inspiratory electromyogram (EMG) activity was recorded from the medial scalene and costal diaphragm. Isometric contractile and fatigue properties were evaluated in vitro. Muscle fibers were classified histochemically and immunohistochemically. Individual fiber cross-sectional areas (CSA) and succinate dehydrogenase (SDH) activities were determined quantitatively. Myosin heavy chain (MHC) isoforms were identified by SDS-PAGE, and their proportions were determined by scanning densitometry. All Emp animals exhibited spontaneous scalene inspiratory EMG activity during quiet breathing, whereas the scalene muscles of controls (Ctl) were silent. There were no differences in contractile and fatigue properties of the scalene between Ctl and Emp. In Emp, the relative amount of MHC2Awas 15% higher whereas that of MHC2X was 14% lower compared with Ctl. Similarly, the proportion of type IIa fibers increased significantly in Emp animals with a concomitant decrease in IIx fibers. CSA of type IIx fibers were significantly smaller in Emp compared with Ctl. SDH activities of all fiber types were significantly increased by 53 to 63% in Emp. We conclude that with Emp the actively recruited scalene exhibits primary-like inspiratory activity in the hamster. Adaptations of the scalene with Emp likely relate both to increased loads and to factors intrinsic to muscle architecture and chest mechanics.

ELECTROPHYSIOLOGICAL RECORDINGS FROM OXYTOCINERGIC NEURONES DURING SUCKLING IN THE UNANAESTHETIZED LACTATING RAT

1981 ◽  
Vol 90 (2) ◽  
pp. 255-265 ◽  
Author(s):  
A. J. S. SUMMERLEE ◽  
D. W. LINCOLN
Keyword(s):  
High Frequency ◽  
Action Potentials ◽  
Milk Ejection ◽  
Extracellular Recordings ◽  
Electrophysiological Recordings ◽  
Oxytocin Release ◽  
Anaesthetized Rats ◽  
Freely Moving ◽  
Frequency Burst ◽  
Stimulation Of

A method is described for making extracellular recordings of the spontaneous activity of single hypothalamic neurones in unanaesthetized, freely moving, lactating rats using chronically implanted micro-wire electrodes. Extracellular recordings taken from individual neurones were maintained for periods of between 1 and 12 days. These records were not affected by any normal movement of the animal. As several micro-wires were implanted into each animal it was possible to make simultaneous recordings from several different hypothalamic sites in the same animal. Some recordings were identified as those from magnocellular neurones in the paraventricular nucleus on the basis of antidromic invasion after electrical stimulation of the neurohypophysis. Milk ejection in response to the prolonged sucking of ten or more pups was intermittent, and individual milk ejections recurred at intervals of 2–10 min throughout each period of nursing. The rise in intramammary pressure at milk ejection was associated with a vigorous extensor response from the pups. This was monitored by radar to provide an index of milk ejection in the unanaesthetized rat. Eleven antidromically identified neurones were recorded through 321 milk ejections. Eight of these neurones displayed a transient (2–6 s) and very substantial acceleration in discharge at the time predicted for oxytocin release, i.e. 10–12 s before milk ejection. The background discharge of these cells was 0·1–2·6 action potentials/s; this increased to 16–50 action potentials/s during the brief period of accelerated activity. Twenty-five neurones were studied during 365 milk ejections in rats which did not have a stimulating electrode implanted in the neurohypophysis. Thirteen of these neurones displayed a burst of high frequency discharge before each milk ejection, similar to that described for the antidromically identified neurones. Two of the non-responsive cells displayed a phasic pattern of discharge, characteristic of vasopressinergic neurone discharge recorded in anaesthetized rats. These observations of putative oxytocinergic neurones in unanaesthetized, freely moving rats are identical with those previously made on anaesthetized rats, and establish that the high frequency burst of electrical activity displayed by magnocellular neurones some 10–12 s before milk ejection is responsible for oxytocin release under normal physiological circumstances.

Patterns of gill ventilation in some decapod Crustacea

2009 ◽  
Vol 150 (4) ◽  
pp. 401-411 ◽  
Author(s):  
K. D. Arudpragasam ◽  
E. Naylor
Keyword(s):  
Decapod Crustacea ◽  
Gill Ventilation

Functional integrity of intrinsic cardiac nerves located over an acute transmural myocardial infarction

1987 ◽  
Vol 65 (1) ◽  
pp. 64-69 ◽  
Author(s):  
R. D. Janes ◽  
D. E. Johnstone ◽  
J. A. Armour
Keyword(s):  
Myocardial Infarction ◽  
Coronary Artery ◽  
Ventricular Fibrillation ◽  
Action Potentials ◽  
Blue Staining ◽  
C Fibers ◽  
Compound Action Potentials ◽  
Intrinsic Cardiac Nerves ◽  
Compound Action ◽  
Cardiac Nerves

Acute transmural myocardial infarction has been reported to functionally denervate the normal myocardium distal to the infarcted zone by interrupting neurotransmission in axons coursing in the subepicardial region of the myocardial necrosis. To directly investigate the viability of such neurotransmission, the effects of acute transmural myocardial infarction on conduction in the intrinsic cardiac nerves overlying and distal to an experimentally induced acute transmural myocardial infarction were studied. In eight dogs, during control states electrical stimulation of the epicardium adjacent to a coronary artery produced compound action potentials in the more cranially located cardiopulmonary nerves. Thereafter, in four dogs an acute transmural myocardial infarction was produced by injecting rapidly hardening latex into a major diagonal branch of the left anterior descending coronary artery. Epicardial stimulation over the infarct, as well as proximal or distal to it, produced compound action potentials that conducted at normal velocities for at least 12 h postinfarction. The transmural extent of the infarct was verified with tetrazolium blue staining at the end of the experiment. In the other four dogs, compound action potentials were generated in cardiopulmonary nerves as described above and then ventricular fibrillation was produced to assess the effects of global anoxia on the function of axons coursing in cardiac nerves. Following the onset of ventricular fibrillation, compound action potentials were generated in these nerves in C fibers for up to 2 h, in B fibers for up to 4 h, and in A fibers for at least 12 h. However, the conduction velocities of these axons was gradually reduced over these periods of time, indicating that, in contrast to the function of axons coursing over a transmural myocardial infarction, their function gradually deteriorated. Thus, by directly assessing the function of axons coursing over a transmural infarction, it is concluded that an acute transmural myocardial infarction does not significantly modify the function of intrinsic cardiac nerves coursing over such an infarct.

scholarly journals An Analysis of Waving Behaviour: An Alternative Motor Programme for the Thoracic Appendages of Decapod Crustacea

1983 ◽  
Vol 102 (1) ◽  
pp. 59-77
Author(s):  
V. M. PASZTOR ◽  
F. CLARAC
Keyword(s):  
Natural Habitat ◽  
Frequency Range ◽  
Equal Frequency ◽  
Metachronal Wave ◽  
The Third ◽  
Decapod Crustacea ◽  
Gill Ventilation ◽  
Two Sides ◽  
Motor Programme ◽  
Slow Frequency

1. Decapod Crustacea display a slow metachronal rhythm of the third maxillipeds and pereiopod pairs one to four when undisturbed in the natural habitat. The dactyl tips are lifted off the substrate, and the unweighted limbs promote and remote at a slow frequency (range for all species 9–30 min−1). Movement is limited to the T-C joint. 2. This behaviour, called waving, has been observed in many macrurans and an analogous activity, limited to the third maxillipeds, has been seen in several brachyurans. 3. Analysis of EMGs shows: (a) the promotor activity increases in strength during a burst due to facilitation and motoneurone recruitment; (b) the rhythm period is stable throughout long waving sessions; (c) the promotor and remotor strokes are of equal duration and co-vary with period. 4. Ipsilateral coupling is strong, with equal phases between adjacent limbs of 0.05. The metachronal wave can pass anteriorly or posteriorly along an ipsilateral row. 5. Bilateral coupling is weak. The two sides maintain equal frequency, and antiphasic coordination between the two ipsilateral sets of limbs is favoured. 6. Possible functions for waving include gill grooming and supplementary gill ventilation. 7. Comparisons between waving and other rhythmical motor programmes are discussed. Waving is an alternative programme for the walking legs, and is expressed when proprioceptive feedback is reduced.

Prolonged force increase following a high-frequency burst is not due to a sustained elevation of [Ca2+]i

2002 ◽  
Vol 283 (1) ◽  
pp. C42-C47 ◽  
Author(s):  
F. Abbate ◽  
J. D. Bruton ◽  
A. De Haan ◽  
H. Westerblad
Keyword(s):  
Skeletal Muscle ◽  
High Frequency ◽  
Action Potentials ◽  
Stimulation Frequency ◽  
Single Fibers ◽  
Force Increase ◽  
Frequency Burst ◽  
Sustained Increase

A brief high-frequency burst of action potentials results in a sustained force increase in skeletal muscle. The present study investigates whether this force potentiation is the result of a sustained increase of the free myoplasmic [Ca2+] ([Ca2+]i). Single fibers from mouse flexor brevis muscles were stimulated with three impulses at 150 Hz (triplet) at the start of a 350-ms tetanus or in the middle of a 700-ms tetanus; the stimulation frequency of the rest of the tetanus ranged from 20 to 60 Hz. After the triplet, force was significantly ( P < 0.05) increased between 17 and 20% when the triplet was given at the start of the tetanus and between 5 and 18% when the triplet was given in the middle ( n = 7). However, during this potentiation, [Ca2+]iwas not consistently increased. Hence, the increased force following a high-frequency burst is likely due to changes in the myofibrillar properties.

Responses of single facial taste fibers in the sea catfish, Arius felis, to amino acids

1991 ◽  
Vol 66 (1) ◽  
pp. 247-260 ◽  
Author(s):  
W. Michel ◽  
J. Caprio
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Action Potentials ◽  
Average Rate ◽  
Present Report ◽  
Taste Buds ◽  
Fiber Types ◽  
Chorda Tympani Nerve ◽  
Taste System ◽  
Stimulus List

1. Taste buds in catfish are found not only within the oropharyngeal cavity, as in mammals, but are also located along the external body surface of the animal from the barbels and lips to the caudal fin. Because these taste buds are innervated by the facial (cranial VII) nerve, the extraoral taste system of catfish is analogous to the mammalian taste system of the anterior two-thirds of the tongue, which contains taste buds innervated by the chorda tympani nerve, and of the soft palate and nasoincisor ducts, which contain taste buds innervated by the greater superficial petrosal nerve. 2. The majority of information concerning the specificity of individual taste fibers in vertebrates has been obtained primarily in mammals to stimuli representing the four basic human taste qualities (i.e., salty, sweet, sour, and bitter). In the present report, we examine the evidence for gustatory fiber types within the stimulus class of amino acids, compounds known to be especially relevant gustatory stimuli for catfish and other teleosts. 3. Action potentials were recorded from 60 individual facial taste neurons obtained from 28 sea catfish (Arius felis). Stimuli were 10(-4) M concentrations of L-alanine, D-alanine, glycine, L-proline, L-histidine, and L-arginine, compounds selected from an original stimulus list of 28 amino acids. Responses were quantified as the number of action potentials evoked at various time intervals from the first 0.5 s up to 10 s of response time. 4. The spontaneous activity of 42 fully characterized neurons was 0.8 +/- 2.1 SD spikes/3 s. The average rate of spike discharge increased 50-fold during stimulation with the most effective amino acid (42 +/- 31 spikes/3 s, mean +/- SD). The majority of the sampled neurons were not narrowly tuned to the amino acid stimulants tested (mean breadth of responsiveness, H = 0.60; range 0-0.95). 5. Hierarchical cluster analysis of the fully characterized neurons identified two large and two small groups of cells. The largest group (n = 22) of neurons was stimulated most by L-alanine and glycine; the other large group (n = 17) was stimulated most by D-alanine. For this latter group, the response to glycine was relatively low, whereas the responses to L-alanine varied from 0 to nearly 100% of the D-alanine response.(ABSTRACT TRUNCATED AT 400 WORDS)

Gill Ventilation Volumes, Oxygen Consumption and Respiratory Rhythms in Carcinus Maenas (L.)

1964 ◽  
Vol 41 (2) ◽  
pp. 309-321
Author(s):  
K. D. ARUDPRAGASAM ◽  
E. NAYLOR
Keyword(s):  
Carbon Dioxide ◽  
Oxygen Consumption ◽  
Prolonged Exposure ◽  
Respiratory Activity ◽  
Carcinus Maenas ◽  
Oxygen Depletion ◽  
Decapod Crustacea ◽  
Gill Ventilation ◽  
Respiratory Rhythms ◽  
Pumping Activity

1. An apparatus is described for continuously measuring gill ventilation volumes in crabs. 2. Large Carcinus pump about 1 c.c./g./min. and consume oxygen at the rate of about 0.03 c.c./g./hr. whilst smaller specimens pump up to 1.5 c.c./g./min. and consume up to 0.1 c.c./g./hr. Freshly collected crabs show persistent tidal and 24 hr. rhythms of pumping activity and oxygen consumption. 3. In response to oxygen depletion Carcinus shows increased rates of gill ventilation and increased percentage utilization. Prolonged exposure to increased carbon dioxide results in a short-lived inhibition followed by over-compensation and then progressive inhibition of respiratory activity. 4. The results are discussed in relation to previous work on respiration in other decapod Crustacea.

Hydrostatic pressures and movements of the lamprey, Petromyzon, during suction, olfaction, and gill ventilation

1972 ◽  
Vol 50 (9) ◽  
pp. 1215-1223 ◽  
Author(s):  
Norman Gradwell
Keyword(s):  
Ambient Pressure ◽  
Pressure Waveform ◽  
Quiet Breathing ◽  
Water Tube ◽  
Gill Ventilation ◽  
Tongue Movements

Sucker pressures are negative relative to ambient pressure, except for the sucker's anterior periphery, where positive pressures prevail. Pressures associated with small rhythmic as well as large sporadic branchial movements are transmitted to the sucker and naris. However, sucker pressures (as great as −90 to 110 cm H2O) associated with tongue movements are not transmitted to the naris or gill pouches. Manual abduction of the sucker caused suction to exceed −120 cm H2O before disengagement. The complex sucker pressure waveform suggests that it is generated by branchial movements combined with some other factors, as yet unknown. During quiet breathing there is no apparent intermixing of water between different gill pouches via their internal confluence with the water tube.

Comparison of phrenic motoneuron activity during eupnea and gasping

1981 ◽  
Vol 50 (5) ◽  
pp. 994-998 ◽  
Author(s):  
W. M. St John ◽  
D. Bartlett
Keyword(s):  
Phrenic Nerve ◽  
Action Potentials ◽  
Single Fiber ◽  
Discharge Frequency ◽  
Fiber Types ◽  
Unit Discharge ◽  
Phrenic Motoneurons ◽  
Motoneuron Activity ◽  
Phrenic Motoneuron ◽  
Pontomedullary Junction

Single-fiber phrenic nerve action potentials were recorded together with activity of contralateral whole phrenic nerve rootlets during eupnea and gasping in decerebrate, cerebellectomized, vagotomized, paralyzed, and ventilated cats. Gasping was reversibly produced by cooling a fork thermode positioned through the pontomedullary junction. In eupnea, phrenic motoneurons were distributed into "early" and "late" populations relative to their onset of activity during inspiration. During gasping, however, both fiber types typically commenced activity at the beginning of the phrenic nerve burst. Moreover, late fibers, but not early units, exhibited an augmentation of discharge frequency with the onset of gasping. The concentration of activity of all phrenic motoneurons at the beginning of inspiration and the increase in late-unit discharge frequency account for the faster rise of the gasp as compared with the eupneic breath. It is concluded that the pattern of phrenic nerve activation during gasping differs fundamentally from that during eupnea. These results support the concept that mechanisms underlying the neurogenesis of gasping and eupnea may not be identical.

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