The Role of the outer Conducting Epithelium in the Behaviour of Salp Oozooids

1982 ◽  
Vol 62 (1) ◽  
pp. 125-132 ◽  
Author(s):  
Q. Bone
Keyword(s):  
Electrical Stimulation ◽  
Locomotor Activity ◽  
Gap Junctions ◽  
Action Potentials ◽  
Sensory Cells ◽  
Similar System ◽  
Locomotor Behaviour ◽  
The Brain ◽  
Stimulation Of

INTRODUCTIONBoth the inner and outer epithelia of salps propagate action potentials (Mackie & Bone, 1977). Skin pulses in the outer epithelium underlying the test (OSPs) evoked by mechanical or electrical stimulation of the epithelium ‘enter’ the brain and may alter the regular rhythmic locomotor activity (Mackie & Bone, 1977; Anderson et al. 1979). The route of'entry’ has not been determined, but has been assumed to be via the axons of the scattered mechanoreceptor sensory cells lying in the outer epithelium. The OSP system would thus operate to extend the sensory field of such cells, as in the appendicularian Oikopleura (Bone & Mackie, 1975; Bone & Ryan, 1979) where two sensory cells are coupled to a conducting epithelium.Salps alternate generations between the solitary asexual oozooid, and the aggregated sexual blastozooids (budded from the stolon of the oozooid). The linked blastozooids form chains, along which OSPs pass to regulate the locomotor behaviour of individual zooids in the chain. The zooids are not linked by gap junctions, and OSPs pass along the chain in a complex.manner, involving alternating epithelioneural and neuroepithelial synapses (Bone, Anderson & Pulsford, 1980; Anderson & Bone, 1980). The OSP system of the oozooid generation is less well understood, although it is known that OSPs in the outer epithelium of the oozooid propagate into the stolon, where they have been studied by Anderson (1979). This paper shows that oozooids possess a similar system of neuroepithelial synapses to that of blastozooids, and that these ‘ drive’ OSPs in the same way as occurs during the regenerative transmission of OSPs along the blastozooid chain.

Role of serotonin and noradrenalin in mechanisms of hypothalamic reg-ulation of experimental dystrophy of the retina

2015 ◽  
Vol 5 (4) ◽  
pp. 137-142
Author(s):  
Miryusifova Ch. M. ◽  
Mohammadova S. I. ◽  
Azizov A. A. ◽  
Mammadov Z. G.
Keyword(s):  
Electrical Stimulation ◽  
Site Effects ◽  
Pigment Epithelium ◽  
Retinal Dystrophy ◽  
Visual Analyzer ◽  
Hypothalamic Regulation ◽  
The Brain ◽  
Stimulation Of ◽  
Oppo Site

  The features of the influence of electrical stimulation of the monoaminergic (MA) nuclei of the brain (nR, LC) on effects of the hypothalamic regulation of retinal electrogenesis in condition of experimental retinal dystrophy were studied It is shown that electrical stimulation of the suprachiasmatic nucleus of the hypothalamus (SCH) for 10 days on the background of the destruction of the pigment epithelium leads to the restoration of parameters as electro-retinogramm (ERG) and of the capacities of various structures of the visual analyzer. However, these effects are of short duration and quickly leveled. Preview activation of the various components MA-ergic system of the brain tends to have mixed influence of the effects of hypothalamic regulation. It is shown that the stimulation of nR increases the effects of SCH nuclei of the hypothalamus. In this environment, the recovery of the amplitude of the parameters from recommendation to photostimulation are stored during the time of testing (12 days). In contrast, stimulation of the LC leads to the oppo-site effects. In the current study, we discuss possible mechanisms of MA-ergic neuromodulation of plasticity of the various components of the visual system of the brain.

Communication between individuals in salp chains. II. Physiology

1980 ◽  
Vol 210 (1181) ◽  
pp. 559-574 ◽  
Keyword(s):  
Action Potentials ◽  
Synaptic Activity ◽  
The Other ◽  
Reverse Direction ◽  
Sensory Cells ◽  
Outer Skin ◽  
Chemical Synapses ◽  
The Brain ◽  
Stimulation Of

When stimulated, salp chains achieve rapid coordinated changes in locomotion by the spread of epithelial action potentials or outer skin pulses (o. s. ps) from one zooid to the next along the chain. This process involves alternating epithelioneural and neuroepithelial chemical synapses. Each zooid is linked to another in the chain by two asymmetric attachment plaques; these are polarized so that transmission of o. s. ps proceeds from one zooid to the next in one direction at one plaque, and in the reverse direction at the other plaque. Sensory cells at the plaques send axons to the brain; they are not electrically coupled to the conducting epithelium in which they lie. Input from the plaque sensory cells affects the swimming generator in the brain (causing locomotor changes) and evokes synaptic activity at neuroepithelial synapses around the brain. This gives rise to o. s. ps that are conducted around the whole of the outer epithelium of the zooid and are detected at the plaques by the sensory cells of adjacent zooids. Severe stimulation of a zooid in the chain induces all zooids to separate; possible mechanisms of separation are discussed.

Tetrodotoxin-resistant release of ATP from superfused rabbit detrusor muscle during electrical field stimulation in the presence of luciferin–luciferase

1984 ◽  
Vol 62 (1) ◽  
pp. 153-156 ◽  
Author(s):  
Archana Chaudhry ◽  
John W. Downie ◽  
Thomas D. White
Keyword(s):  
Action Potentials ◽  
Electrical Field Stimulation ◽  
Detrusor Muscle ◽  
Electrical Field ◽  
Stimulation Parameters ◽  
Rabbit Bladder ◽  
Firefly Luciferin ◽  
Rabbit Urinary Bladder ◽  
Stimulation Of

The present study was carried out to assess the possible role of ATP in the noncholinergic, nonadrenergic transmission in the rabbit urinary bladder. When rabbit detrusor muscle strips were superfused with medium containing firefly luciferin–luciferase and stimulated transmurally at low stimulation parameters, tetrodotoxin-sensitive contractions were obtained but no release of ATP could be detected. However, at somewhat higher stimulation parameters, release of ATP was observed. This release of ATP was not diminished by tetrodotoxin indicating that ATP was not likely released as a result of propagated action potentials in nerves. Because contractions persisted in the presence of tetrodotoxin, it is possible that the ATP might have been released as a result of direct electrical stimulation of the muscle. These results do not support the idea that ATP is released as a neurotransmitter in the rabbit bladder.

Electronmicroscopic and electrophysiological studies of the teat branch of the XIII thoracic nerve: relationship with lactation in the rat

1988 ◽  
Vol 118 (3) ◽  
pp. 471-483 ◽  
Author(s):  
L. M. Voloschin ◽  
E. Décima ◽  
J. H. Tramezzani
Keyword(s):  
Electrical Stimulation ◽  
Conduction Velocity ◽  
Action Potentials ◽  
Silent Period ◽  
High Amplitude ◽  
Milk Ejection ◽  
Nerve Activity ◽  
Thoracic Nerve ◽  
Myelinated Fibres ◽  
Stimulation Of

ABSTRACT Electrical stimulation of the XIII thoracic nerve (the 'mammary nerve') causes milk ejection and the release of prolactin and other hormones. We have analysed the route of the suckling stimulus at the level of different subgroups of fibres of the teat branch of the XIII thoracic nerve (TBTN), which innervates the nipple and surrounding skin, and assessed the micromorphology of the TBTN in relation to lactation. There were 844 ± 63 and 868 ± 141 (s.e.m.) nerve fibres in the TBTN (85% non-myelinated) in virgin and lactating rats respectively. Non-myelinated fibres were enlarged in lactating rats; the modal value being 0·3–0·4 μm2 for virgin and 0·4–0·5 μm2 for lactating rats (P > 0·001; Kolmogorov–Smirnov test). The modal value for myelinated fibres was 3–6 μm2 in both groups. The compound action potential of the TBTN in response to electrical stimulation showed two early volleys produced by the Aα- and Aδ-subgroups of myelinated fibres (conduction velocity rate of 60 and 14 m/s respectively), and a late third volley originated in non-myelinated fibres ('C') group; conduction velocity rate 1·4 m/s). Before milk ejection the suckling pups caused 'double bursts' of fibre activity in the Aδ fibres of the TBTN. Each 'double burst' consisted of low amplitude action potentials and comprised two multiple discharges (33–37 ms each) separated by a silent period of around 35 ms. The 'double bursts' occurred at a frequency of 3–4/s, were triggered by the stimulation of the nipple and were related to fast cheek movements visible only by watching the pups closely. In contrast, the Aα fibres of the TBTN showed brief bursts of high amplitude potentials before milk ejection. These were triggered by the stimulation of cutaneous receptors during gross slow sucking motions of the pup (jaw movements). Immediately before the triggering of milk ejection the mother was always asleep and a low nerve activity was recorded in the TBTN at this time. When reflex milk ejection occurred, the mother woke and a brisk increase in nerve activity was detected; this decreased when milk ejection was accomplished. In conscious rats the double-burst type of discharges in Aδ fibres was not observed, possibly because this activity cannot be detected by the recording methods currently employed in conscious animals. During milk ejection, action potentials of high amplitude were conveyed in the Aα fibres of the TBTN. During the treading time of the stretch reaction (SR), a brisk increase in activity occurred in larger fibres; during the stretching periods of the SR a burst-type discharge was again observed in slow-conducting afferents; when the pups changed nipple an abrupt increase in activity occurred in larger fibres. In summary, the non-myelinated fibres of the TBTN are increased in diameter during lactation, and the pattern of suckling-evoked nerve activity in myelinated fibres showed that (a) the double burst of Aδ fibres, produced by individual sucks before milk ejection, could be one of the conditions required for the triggering of the reflex, and (b) the nerve activity displayed during milk-ejection action may result, at least in part, from 'non-specific' stimulation of cutaneous receptors. J. Endocr. (1988) 118, 471–483

scholarly journals NEURONAL-GLIAL MEMBRANE CONTACTS DURING PESSIMAL ELECTRICAL STIMULATION

2020 ◽  
Vol 28 (3) ◽  
pp. 35-50
Author(s):  
Oleg S. Sotnikov ◽  
Svetlana S. Sergeeva ◽  
Tat'yana I. Vasyagina
Keyword(s):  
Electrical Stimulation ◽  
Gap Junctions ◽  
De Novo ◽  
Laboratory Rats ◽  
Transmission Electron ◽  
Layer Structures ◽  
Dense Substance ◽  
Membrane Contacts ◽  
Glial Membrane ◽  
Stimulation Of

After the creation of a method for obtaining inter-neuronal gap junctions in a nervous system devoid of glia, it is expedient to reproduce gap neuronal-glial contacts on a model that also contains hybrid neuronal-glial gap junctions, which, as you know, are functionally fundamentally different from inter-neuronal contacts. The experiments were carried out on the truncus sympathicus ganglia of laboratory rats using pessimal electrical stimulation and transmission electron microscopy. Electrical activation of ganglia with a frequency of up to 100 Hz revealed local and widespread variants of various neuronal-glial connections (contacts, bridges), fringed with peri-membrane filamentous proteins. They had a blurred veil that masked two-layer neuro-membranes. Some of the contacts resembled slit or dense 5-layer structures without a visible inter-neuronal slit, but with an extreme decrease in the thickness of the contact slit. The main result of the experiments was the formation, in addition to slotted, multiple septate (ladder) contacts. Relatively independent aggregates of the electron-dense substance of the septa were located inside the intercellular gaps, crossing both adjacent membranes, and, possibly, permeate of them. Near-membrane, poorly outlined pyramid-like protein cones associated with both cell membranes were also formed. Such membranes appeared to be dotted-dashed, that is, not continuous. A significant number of septic contact membranes had endocytic invaginations (invaginations) facing neuroplasm with pyramid-like marginal projections. All reactive altered structures that have arisen de novo are considered by the authors as developed under the influence of frequency electrical stimulation of denaturation and aggregation of intrinsic and perimembrane proteins.

Sign in / Sign up

Export Citation Format

Share Document