scholarly journals The Photoreceptors of Lampreys

1935 ◽  
Vol 12 (3) ◽  
pp. 229-238 ◽  
Author(s):  
J. Z. YOUNG
Keyword(s):  
Spinal Cord ◽  
Latent Period ◽  
Lateral Line ◽  
The Body ◽  
Direct Stimulation ◽  
Normal Behaviour ◽  
Motor Responses ◽  
Lateral Line Nerve ◽  
Stimulation Of ◽  
Do So

1. The tail of larval and adult L. planeri and adult L. fluviatilis contains a photoreceptive mechanism involving an initial short sensitization period, and a latent period. 2. The impulses initiated by the photochemical change are carried in the lateral line nerves, as is shown by the facts that section of these nerves abolishes the response, whereas section of the spinal cord does not do so. 3. Motor responses are only occasionally seen after illumination of parts of the body other than the tail. These responses are apparently due to direct stimulation of the spinal cord, and can be regularly elicited if the pigment protecting the latter be removed. 4. Motor responses may follow illumination of the head, either of larvae or adults, but only after illumination periods much longer than are necessary to obtain a response from the tail. 5. The responses play a part in the normal behaviour of the animals by assisting them to bury themselves completely in the mud. 6. The stimulus of illumination of the tail simply initiates swimming movements, and there is no orientation of the animal with reference to the direction of the light. This is confirmed by the observation that, following illumination of the tail from one side, the first movement of the head may be either towards or away from the side stimulated. Further, after section of one lateral line nerve only no forced movements occur on illumination. The reaction may thus be described as a photokinesis, and does not involve any true topotaxis, its effect is to prevent the animal remaining in any illuminated area.

scholarly journals VI. —Anaphylaxis and anaphylatoxins

1923 ◽  
Vol 211 (382-390) ◽  
pp. 273-315 ◽  
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Guinea Pig ◽  
Anaphylactic Shock ◽  
The Body ◽  
Muscle Fibres ◽  
Direct Stimulation ◽  
Fundamental Conception ◽  
The Central Nervous System ◽  
Stimulation Of

In the study of the phenomena of anaphylaxis there are certain points on which some measure of agreement seems to have been attained. In the case of anaphylaxis to soluble proteins, with which alone we are directly concerned in this paper, the majority of investigators probably accept the view that the condition is due to the formation of an antibody of the precipitin type. Concerning the method, however, by which the presence of this antibody causes the specific sensitiveness, the means by which its interaction with the antibody produces the anaphylactic shock, there is a wide divergence of conception. Two main currents of speculation can be discerned. One view, historically rather the earlier, and first put forward by Besredka (1) attributes the anaphylactic condition to the location of the antibody in the body cells. There is not complete unanimity among adherents of this view as to the nature of the antibody concerned, or as to the class of cells containing it which are primarily affected in the anaphylactic shock. Besredka (2) himself has apparently not accepted the identification of the anaphylactic antibody with a precipitin, but regards it as belonging to a special class (sensibilisine). He also regards the cells of the central nervous system as those primarily involved in the anaphylactic shock in the guinea-pig. Others, including one of us (3), have found no adequate reason for rejecting the strong evidence in favour of the precipitin nature of the anaphylactic antibody, produced by Doerr and Russ (4), Weil (5), and others, and have accepted and confirmed the description of the rapid anaphylactic death in the guinea-pig as due to a direct stimulation of the plain-muscle fibres surrounding the bronchioles, causing valve-like obstruction of the lumen, and leading to asphyxia, with the characteristic fixed distension of the lungs, as first described by Auer and Lewis (6), and almost simultaneously by Biedl and Kraus (7). But the fundamental conception of anaphylaxis as due to cellular location of an antibody, and of the reaction as due to the union of antigen and antibody taking place in the protoplasm, is common to a number of workers who thus differ on details.

Mormyromast electroreceptor organs and their afferent fibers in mormyrid fish. II. Intra-axonal recordings show initial stages of central processing

1990 ◽  
Vol 63 (2) ◽  
pp. 303-318 ◽  
Author(s):  
C. C. Bell
Keyword(s):  
Lateral Line ◽  
Electric Organ Discharge ◽  
Electric Organ ◽  
Direct Stimulation ◽  
Postsynaptic Potentials ◽  
Central Processing ◽  
Refractory Periods ◽  
Synaptic Potentials ◽  
Afferent Fibers ◽  
Stimulation Of

1. Physiologically and morphologically identified primary afferent fibers from mormyromast electroreceptor organs were recorded intracellularly. The fiber recordings were made from the nerve root of the posterior lateral line nerve, where the fibers enter the brain, and from the electrosensory lateral line lobe (ELL), near the central terminals of the fibers. 2. The intracellular recordings reveal a variety of potentials, synaptic and nonsynaptic, in addition to the large orthodromic action potentials from the periphery. The goal of the present study was to describe and interpret these various potentials in mormyromast afferent fibers as a first step in understanding the processing of electrosensory information in ELL. 3. Three types of synaptic potentials were recorded inside mormyromast afferent fibers: 1) electric organ corollary discharge (EOCD) excitatory postsynaptic potentials (EPSPs), driven by the motor command that elicits the electric organ discharge (EOD); 2) EPSPs evoked by electrosensory stimulation of electroreceptors in the skin near the electroreceptor from which the recorded fiber originates or by direct stimulation of an electrosensory nerve; and 3) inhibitory postsynaptic potentials (IPSPs) evoked by electrosensory stimulation of more distant electroreceptors. These synaptic potentials can be attributed to synaptic input to postsynaptic cells in ELL that is observed inside the afferent fibers because of electrical synapses between the fibers and the postsynaptic cells. 4. The peripherally evoked EPSPs could frequently be shown to be unitary. The unitary EPSPs were identical to the orthodromic spikes in originating from a single electroreceptor, in threshold, and in latency shift with increasing stimulus intensity. These similarities suggest that the unitary EPSPs are electrotonic EPSPs caused by impulses in other mormyromast afferent fibers that terminate on some of the same postsynaptic cells as the recorded fiber. The peripherally evoked IPSPs had a longer latency than the EPSPs or orthodromic spikes, requiring the presence of an inhibitory interneuron. 5. The peripherally evoked EPSPs, both unitary and nonunitary, show absolute refractory periods of 3-8 ms, followed by relative refractory periods of approximately 8 ms, when tested with two identical stimuli to a nerve. These refractory periods are interpreted as because of refractoriness in the fine preterminal branches of the axonal arbor. 6. A depolarizing afterpotential is commonly associated with the orthodromic spike and probably results from the successful propagation of the spike into the entire terminal arbor. The depolarizing afterpotential has a refractory period that is similar to that of the peripherally evoked EPSPs and that is also interpreted as refractoriness in the fine preterminal branches.(ABSTRACT TRUNCATED AT 400 WORDS)

Memoirs: The Neuro-Muscular Mechanism of the Gill of Pecten

1930 ◽  
Vol s2-73 (291) ◽  
pp. 365-392
Author(s):  
S. B. SETNA
Keyword(s):  
Feeding Habits ◽  
Adductor Muscle ◽  
The Body ◽  
Muscle Fibres ◽  
Direct Stimulation ◽  
Gill Filaments ◽  
Lateral Extent ◽  
Branchial Nerve ◽  
The Individual ◽  
Stimulation Of

Experimental. 1. The contraction of the adductor-muscle which follows stimulation of the palial nerve is preceded by a marked contraction of the ctenidial axis, so that the gill contracts before the adductor-muscle becomes active. This movement of the ctenidium is abolished if the main branchial nerve is cut near its origin. 2. The gills of Pecten possess a neuromuscular mechanism which is to some extent independent of the rest of the body, so that excised gills when stimulated react in the same way as an attached gill. 3. The lamellae of the gill possess two distinct types of movement. (a) When the surface of the gill is stimulated by contact with a glass rod or by carmine particles, the frontal surfaces of the two lamellae approach each other; the movement very often being executed by the lamella which is not actually being stimulated. The lateral extent of these movements (concertina movements) is roughly proportional to the intensity of the stimulus. Such movements normally appear to transfer the bulk of the material on to the mantle. Separation of the main branchial nerve abolishes these movements. (b) Each principal filament is capable of moving the ordinary filaments to which it is attached. This movement (flapping movement) is due to the movements of the interfilamentar junctions which alternatively move up and down at right angles to their length. This motion is independent of the branchial nerve and can be produced by direct stimulation of very tiny pieces of the individual filaments. 4. The significance of gill movements to feeding habits is discussed. The course of food particles depends on the nature of the stimuli affecting the gill. Histological. 5. The ctenidial axis and the principal filaments have a stratum of anastomosing nerve-cells which appear to form a true nerve-net comparable to that of the mantle. 6. The gill receives nerve-fibres from two sources, the brain and the visceral ganglion. The subsidiary branchial nerve is a structure hitherto unknown in the molluscan gill; so far its function is unknown. Each gill has four main longitudinal nerve-trunks. 7. The osphradium of the gill has a much more extensive distribution than has hitherto been supposed. 8. Two sets of muscles exist at the base of the gill-filaments, and these are responsible for movements of the lamellae. The muscle-fibres are non-striated. 9. The principal filaments are connected to the ordinary filaments by processes containing true muscle-cells, and by these cells movements of the filaments are effected.

The Activity of Lateral-Line Efferent Neurones in Stationary and Swimming Dogfish

1972 ◽  
Vol 57 (2) ◽  
pp. 435-448 ◽  
Author(s):  
B. L. ROBERTS ◽  
I. J. RUSSELL
Keyword(s):  
Lateral Line ◽  
Body Movement ◽  
Cranial Nerves ◽  
Regulatory System ◽  
The Body ◽  
Muscle Fibres ◽  
Sense Organs ◽  
Efferent System ◽  
Natural Stimulation ◽  
Stimulation Of

1. The activity of efferent neurones innervating lateral-line organs on the body of dogfish was followed by recording from filaments of cranial nerve X in 41 decerebrate preparations. 2. The efferent nerves were not spontaneously active. 3. Tactile stimulation to the head and body, vestibular stimulation and noxious chemical stimulation were followed by activity of the efferent nerves. 4. In contrast, natural stimulation of lateral-line organs (water jets) did not reflexly evoke discharges from the efferent fibres. 5. Reflex efferent responses were still obtained to mechanical stimulation even after the lateral-line organs had been denervated. 6. Electrical stimulation of cranial nerves innervating lateral-lines organs was followed by reflex activity of the efferent fibres. But similar stimuli applied to other cranial nerves were equally effective in exciting the efferent system. 7. Vigorous movements of the fish, involving the white musculature, were preceded and accompanied by activity of the efferent fibres which persisted as long as the white muscle fibres were contracting. 8. Rhythmical swimming movements were accompanied by a few impulses in the efferent fibres grouped in bursts at the same frequency as the swimming movements. 9. It is concluded that the efferent neurones cannot contribute to a feedback regulatory system because they are not excited by natural stimulation of the lateral-line sense organs. The close correlation found between efferent activity and body movement suggests that the efferent system might operate in a protective manner to prevent the sense organs from being over-stimulated when the fish makes vigorous movements.

scholarly journals Clinical application of evoked spinal cord potentials elicited by direct stimulation of the cord during temporary occlusion of the thoracic aorta

1994 ◽  
Vol 107 (6) ◽  
pp. 1519-1527 ◽  
Author(s):  
Yoshiro Matsui ◽  
Kazutomo Goh ◽  
Norihiko Shiiya ◽  
Toshihumi Murashita ◽  
Masatoshi Miyama ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Thoracic Aorta ◽  
Clinical Application ◽  
Direct Stimulation ◽  
Temporary Occlusion ◽  
Stimulation Of

scholarly journals Evidences of Existence of Serotoninergic Nerves, Enhancing Duodenal Motility

2015 ◽  
Vol 70 (6) ◽  
pp. 718-726
Author(s):  
Viktor Mihajlovich Smirnov ◽  
Dmitrij Sergeevich Sveshnikov ◽  
Igor Leonidovich Myasnikov ◽  
Tat'jana Evgen'evna Kuznecova ◽  
Jurij Nikolaevich Samko
Keyword(s):  
Sympathetic Nerves ◽  
The Body ◽  
Sympathetic Trunk ◽  
Thoracic Cavity ◽  
Internal Organs ◽  
Electrical Nerve Stimulation ◽  
Motor Responses ◽  
Duodenal Motility ◽  
5Ht Receptors ◽  
Stimulation Of

The review is devoted to the mechanism of duodenal motility activation caused by sympathetic nerves. The authors have found that stimulation of the sympathetic trunk in the thoracic cavity in dogs in most cases provide not inhibitory but excitatory motor responses of the duodenum. Excitatory effects were eliminated during 5HT-receptors blockade by promedol and lysergol. Analysis of publications showed that sympathetic trunk contains serotoninergic fibers, providing excitatory motor responses of the duodenum to electrical nerve stimulation. According to histochemical and physiological studies, amount of serotonergic fibers in the sympathetic trunk is several times more than the adrenergic. This means that the body has sertoninergic nerves. Serotoninergic nerve as well as the sympathetic is a collective notion. There are: sympathetic trunks, their ramifications and branches that innervate the internal organs. Since promedol blocks serotonergic nerves, this is plausible cause of constipation in patients after surgical treatment along with the application of this drug.

Escape from Recurring Tactile Stimulation in Branchiomma Vesiculosum

1965 ◽  
Vol 42 (2) ◽  
pp. 307-322 ◽  
Author(s):  
FRANKLIN B. KRASNE
Keyword(s):  
Ventral Nerve Cord ◽  
Tactile Stimulation ◽  
The Body ◽  
Direct Stimulation ◽  
Giant Fibre ◽  
Sensory Ending ◽  
Tactile Stimuli ◽  
Escape Reflex ◽  
Giant Fibres ◽  
Stimulation Of

1. Branchiomma's rapid escape from tactile stimuli is mediated by the pair of giant nerve axons which run the length of the body above the ventral nerve cord. 2. The giant neurons are connected by very stable, polarized junctions to giant motor axons. 3. The giant-fibre escape reflex fails if tactile stimuli are repeated; a non-giant system which continues to cause slower escape eventually fails also. 4. Recovery from reflex failure is slow. 5. The failure of the rapid escape reflex occurs prior to the giant fibre. It is not primarily due to sensory ending accommodation. It cannot be caused by direct stimulation of the giant fibres.

The Giant Fibre Reflex of the Earthworm, Lumbricus Terrestris L

1962 ◽  
Vol 39 (2) ◽  
pp. 219-227
Author(s):  
M. B. V. ROBERTS
Keyword(s):  
Nerve Cord ◽  
Lumbricus Terrestris ◽  
The Body ◽  
Muscle Preparation ◽  
Direct Stimulation ◽  
Giant Fibre ◽  
Low Threshold ◽  
Giant Fibres ◽  
Nerve Muscle ◽  
Stimulation Of

1. A nerve-muscle preparation including the longitudinal musculature and the giant fibres in the nerve cord of the earthworm is described. 2. Direct stimulation of the nerve cord with single shocks of increasing intensity results in two types of response: (a) a low threshold, very small twitch, resulting from a single impulse in the median giant fibre, and (b) a higher threshold, slightly larger twitch, resulting from single impulses in the median and lateral giant fibres. Both responses are highly susceptible to fatigue. 3. Stimulation of the body surface evokes a much more powerful contraction which is associated with a burst of impulses in the giant fibre. The strength of the contraction depends upon the number of impulses in the burst and this in turn upon the intensity and duration of the stimulus.

Monitoring of Spinal Cord Stimulation Evoked Potentials during Thoracoabdominal Aneurysm Surgery

Neurosurgery ◽  
1991 ◽  
Vol 28 (2) ◽  
pp. 325-330 ◽  
Author(s):  
Richard B. North ◽  
Benjamin Drenger ◽  
Charles Beattie ◽  
Robert W. McPherson ◽  
Stephen Parker ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Evoked Potentials ◽  
Evoked Potential ◽  
Conduction Block ◽  
Significant Risk ◽  
Thoracoabdominal Aneurysm ◽  
Direct Stimulation ◽  
Lower Extremity Ischemia ◽  
Extremity Ischemia ◽  
Stimulation Of

Abstract Repair of a thoracoabdominal aneurysm involves a significant risk of ischemic injury to the spinal cord. Standard monitoring of somatosensory evoked potentials, which relies upon peripheral nerve stimulation, becomes nonspecific and insensitive during this surgery when aortic cross-clamping produces lower extremity ischemia causing a peripheral conduction block. Techniques for the insertion of percutaneous epidural electrodes, developed originally for pain management, have been adapted to this setting to permit direct stimulation of the spinal cord for intraoperative monitoring of evoked potentials. The clinical outcome in patients monitored by this technique has been consistent with evoked potential findings.

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