Properties of Interneurones in the Abdominal Nerve Cord of a Dragonfly Nymph

1963 ◽  
Vol 40 (3) ◽  
pp. 541-552
Author(s):  
ANN FIELDEN
Keyword(s):  
Electrical Stimulation ◽  
Nerve Cord ◽  
Afferent Pathway ◽  
Spinal Interneurones ◽  
Dragonfly Nymph ◽  
Afferent Volley ◽  
Frequency Of Stimulation ◽  
Stimulation Of

1. Responses of single interneurones in the abdominal connectives of the dragonfly nymph following electrical stimulation of the segmental nerves were investigated. 2. Excitation and inhibition were seen in fibres with a resting discharge. Repetitive trains of impulses, varying between units and with the source of the afferent volley, were common. 3. Changes in the intensity and frequency of stimulation affected the pattern of the repetitive responses. An increase in the intensity of the volley shortened the latency and increased the length of the train, while an increase in rate reduced the number of impulses. 4. Most interneurones responded to stimulation of more than one afferent pathway. Multisegmental fibres and multiple connexions of fibres were common. 5. These responses are compared with those of spinal interneurones and discussed in relation to their function in the animal.

scholarly journals Physiological characterisation of antennal mechanosensory descending interneurons in an insect (Gryllus bimaculatus, Gryllus campestris) brain

2001 ◽  
Vol 204 (13) ◽  
pp. 2265-2275 ◽  
Author(s):  
Michael Gebhardt ◽  
Hans-Willi Honegger
Keyword(s):  
Electrical Stimulation ◽  
Experimental Evidence ◽  
Nerve Cord ◽  
Ventral Nerve Cord ◽  
Sensory Nerves ◽  
Gryllus Bimaculatus ◽  
Central Origin ◽  
Gryllus Campestris ◽  
Descending Interneurons ◽  
Stimulation Of

SUMMARY We investigated five different descending brain interneurons with dendritic arborizations in the deutocerebrum in the crickets Gryllus bimaculatus and G. campestris. These interneurones convey specific antennal mechanosensory information to the ventral nerve cord and all responded to forced antennal movements. These interneurones coded for velocity and showed preferences for distinct sectors of the total range of antennal movements. Their axons descended into the posterior connective either ipsilateral or contalateral to the cell body. Electrical stimulation of sensory nerves indicated that the interneurons received input from different afferents of the two antennal base segments. One interneuron had a particularly large axon with a conduction velocity of 4.4ms−1. This was the only one of the five interneurons that also received visual input. Its activity was reduced during voluntary antennal movements. The reduction in activity occurred even after de-efferentation of the antenna, indicating that it had a central origin. Although we do not have experimental evidence for behavioural roles for the descending antennal mechanosensory interneurons, the properties described here suggest an involvement in the perception of objects in the path of the cricket.

The Activity of Single Motor Fibres in Arthropods I. The Dragonfly Nymph

1965 ◽  
Vol 42 (3) ◽  
pp. 447-461
Author(s):  
ANN KNIGHTS
Keyword(s):  
Electrical Stimulation ◽  
Temporal Summation ◽  
Reciprocal Relationship ◽  
Response Patterns ◽  
Insect Muscle ◽  
Frequency Sensitivity ◽  
Single Motor ◽  
Dragonfly Nymph ◽  
Central Inhibition ◽  
Stimulation Of

1. Responses to mechanical and electrical stimulation have been investigated in single motor fibres dissected in the segmental nerves of the dragonfly nymph. 2. A large proportion of fibres possessed a background discharge which was often accelerated of inhibited on stimulation. Examples of central inhibition were common. 3. Efferent responses varied in type, delay and regularity, both with the input under stimulation and with the frequency and intensity of the volley. The majority of fibres responded to stimulation of more than one nerve root. 4. In many motor fibres changes in the parameters of stimulation demonstrated a reciprocal relationship between and frequency. An enhanced responsiveness occurred with frequency increases in the range of 10-100/sec. indicatind a considerable importance of temporal summation/facilitation. 5. The characteristic frequency-sensitivity of motor fibres and the variability of their response patterns are discussed in relation to the control of insect muscle.

The release of catecholamines from the adrenal medulla and its modulation by α2-adrenoceptors in the anaesthetized dog

1987 ◽  
Vol 65 (4) ◽  
pp. 550-557 ◽  
Author(s):  
Sylvain Foucart ◽  
Réginald Nadeau ◽  
Jacques de Champlain
Keyword(s):  
Electrical Stimulation ◽  
Adrenal Medulla ◽  
Plasma Concentrations ◽  
Splanchnic Nerve ◽  
Feedback Mechanism ◽  
Adrenal Vein ◽  
Low Frequencies ◽  
Negative Feedback Mechanism ◽  
Frequency Of Stimulation ◽  
Stimulation Of

The adrenal nerve of anaesthetized and vagotomized dogs was electrically stimulated (10 V pulses of 2 ms duration for 10 min) at frequencies of 1, 3, 10, and 25 Hz. There was a correlation between the frequency of stimulation and the plasma concentrations of epinephrine, norepinephrine, and dopamine in the adrenal vein, mainly after the 1st min of stimulation and the maximal concentration was reached sooner with higher frequencies of stimulation. Moreover, the relative percentage of catecholamines released in response to the electrical stimulation was not changed by the frequency of stimulation. To test the hypothesis that a local negative feedback mechanism mediated by α2-adrenoceptors exists in the adrenal medulla, the effects of the systemic administration of clonidine (α2-agonist) and yohimbine (α2-antagonist) on the concentrations of catecholamines in the adrenal vein were evaluated during the electrical stimulation of the adrenal nerve (5 V pulses of 2 ms duration for 3 min) at 3 Hz. Moreover, the effects of the systemic injections of more specific α2-agonist and antagonist (oxymetazoline and idazoxan) were tested on the release of catecholamines in the adrenal vein in response to electrical stimulation of the splanchnic nerve at 1 and 3 Hz frequencies. The injection of 0.5 mg/kg of yohimbine caused a significant increase in the concentrations of epinephrine and norepinephrine in the adrenal vein induced by the electrical stimulation of the adrenal nerve and the injection of 15 μg/kg of clonidine had no effects. In the second series of experiments, the injection of 2 μg/kg of oxymetazoline caused a significant decrease in the release of epinephrine and norepinephrine at 1 Hz, but similarly to clonidine, there were no changes at 3 Hz. In contrast, the release of epinephrine and dopamine in response to electrical stimulation of the splanchnic nerve was increased at 3 Hz after the injection of idazoxan, but not at 1 Hz. It is concluded that the adrenal medulla catecholamines secretion appears to be partly modulated by a presynaptic inhibitory mechanism that involves α2-adrenoceptors. The observation that agonists appear to be more efficient at low frequencies of stimulation while antagonists appear to be more efficient at higher frequencies could be explained by the possibility that adrenal medullary α2-receptors would be saturated at higher frequencies of stimulation.

Some Preliminary Observations on the Effects of Cations on Conduction Processes in the Abdominal Nerve Cord of the Stick Insect, Carausius Morosus

1965 ◽  
Vol 42 (1) ◽  
pp. 1-6
Author(s):  
J. E. TREHERNE
Keyword(s):  
Electrical Stimulation ◽  
Nerve Conduction ◽  
Nerve Cord ◽  
Action Potentials ◽  
Ionic Composition ◽  
Stick Insect ◽  
Carausius Morosus ◽  
Stimulation Of

1. In the haemolymph of the stick insect Carausius morosus the concentration of potassium exceeds that of sodium and the concentration of magnesium exceeds that of calcium. The implications of this situation for nerve conduction have been studied. 2. Conduction is maintained in intact and desheathed preparations of the fourth adbominal ganglion under irrigation with a solution resembling haemolymph in ionic composition. 3. Action potentials recorded in response to electrical stimulation of the nerve cord decline in sodium-free solutions, both in intact and in desheathed preparations. 4. Conduction declines slowly under irrigation with magnesium-free solutions both in intact and in desheathed preparations.

Afferent pathway of systemic pressor response to proximal vagosympathetic stimulation in the dog

1959 ◽  
Vol 197 (4) ◽  
pp. 817-820 ◽  
Author(s):  
William D. Kelly
Keyword(s):  
Blood Flow ◽  
Electrical Stimulation ◽  
Vagus Nerve ◽  
Femoral Artery ◽  
Pressor Response ◽  
Afferent Pathway ◽  
Intact Side ◽  
Thoracic Sympathectomy ◽  
Upper Thoracic ◽  
Stimulation Of

The systemic pressor response to stimulation of the cephalic end of the divided vagosympathetic trunk was studied 1–3 weeks after unilateral stellate ganglionectomy and upper thoracic sympathectomy in 14 dogs. In addition, in four of the animals blood flow to the circulatorily isolated head was measured using either the carotid or veterbral arteries alone for perfusion. In response to electrical stimulation of the proximal vagus, blood flow to the head decreased on the average of 21% on the sympathectomized side and by 55% on the intact side. Nevertheless, the average pressor response as measured in the femoral artery was not significantly altered by sympathectomy in either group. The data are interpreted as indicating that the aforementioned pressor response is mediated by way of afferent visceral fibers in the vagus nerve.

scholarly journals Studies on the in Vitro Interaction of Electrical Stimulation and Ca++ Movement in Sarcoplasmic Reticulum

1966 ◽  
Vol 49 (4) ◽  
pp. 689-715 ◽  
Author(s):  
Kwang S. Lee ◽  
Herbert Ladinsky ◽  
Sin J. Choi ◽  
Y. Kasuya
Keyword(s):  
Electrical Stimulation ◽  
Sarcoplasmic Reticulum ◽  
Inorganic Phosphate ◽  
Muscle Model ◽  
Ca Uptake ◽  
In Vitro Interaction ◽  
Frequency Of Stimulation ◽  
Stimulation Of

Sarcoplasmic reticulum fragments (S.R.F.) were isolated from skeletal and heart muscles. These fragments were found to take up Ca++ very actively from media. When monophasic square waves were passed through the S.R.F. suspension, the Ca++ uptake by S.R.F. was decreased. When the suspension was stimulated electrically after the Ca++ was taken up by S.R.F., the initiation and the cessation of the stimulation were followed by the release and re-uptake of Ca++ by S.R.F., respectively. The degree of inhibition of the Ca++ uptake as well as of the Ca++ release by electrical stimulation was dependent on the voltage and the frequency of stimulation. The presence of inorganic phosphate or oxalate modified the influence of electrical stimulation on the release and the uptake of Ca++ by S.R.F. Attempts were made to observe the release of Ca++ by electrical stimulation from unfractionated sarcoplasmic reticulum remaining in myofibers, and the interaction of the released Ca++ with myofibrils in vitro. For this purpose, the glycerol-extracted fiber was selected as a muscle model, since it contains both sarcoplasmic reticulum and myofibrils. It was found that electrical stimulation of skeletal and heart glycerol-extracted fibers resulted in the contraction of fibers. It appeared that the contraction of glycerol fibers by electrical stimulation was caused by the Ca++ release from sarcoplasmic reticulum by stimulation.

scholarly journals Burst-like conditioning electrical stimulation is more efficacious than continuous stimulation for inducing secondary hyperalgesia in humans

2020 ◽  
Vol 123 (1) ◽  
pp. 323-328 ◽  
Author(s):  
S. Gousset ◽  
A. Mouraux ◽  
E. N. van den Broeke
Keyword(s):  
Electrical Stimulation ◽  
Total Duration ◽  
Secondary Hyperalgesia ◽  
Continuous Stimulation ◽  
Cohen’S D ◽  
Electrical Conditioning ◽  
Nociceptive Input ◽  
Cohen's D ◽  
Frequency Of Stimulation ◽  
Stimulation Of

The aim of the present study was to compare the efficacy of burst-like conditioning electrical stimulation vs. continuous stimulation of cutaneous nociceptors for inducing increased pinprick sensitivity in the surrounding unstimulated skin (a phenomenon referred to as secondary hyperalgesia). In a first experiment ( n = 30), we compared the increase in mechanical pinprick sensitivity induced by 50-Hz burst-like stimulation ( n = 15) vs. 5-Hz continuous stimulation ( n = 15) while maintaining constant the total number of stimuli and the total duration of stimulation. We found a significantly greater increase in mechanical pinprick sensitivity in the surrounding unstimulated skin after 50-Hz burst-like stimulation compared with 5-Hz continuous stimulation ( P = 0.013, Cohen’s d = 0.970). Importantly, to control for the different frequency of stimulation, we compared in a second experiment ( n = 40) 5-Hz continuous stimulation ( n = 20) vs. 5-Hz burst-like stimulation ( n = 20), this time while keeping the total number of stimuli as well as the frequency of stimulation identical. Again, we found a significantly greater increase in pinprick sensitivity after 5-Hz burst-like stimulation compared with 5-Hz continuous stimulation ( P = 0.009, Cohen’s d = 0.868). To conclude, our data indicate that burst-like conditioning electrical stimulation is more efficacious than continuous stimulation for inducing secondary hyperalgesia. NEW & NOTEWORTHY Burst-like electrical conditioning stimulation of cutaneous nociceptors is more efficacious than continuous stimulation for inducing heterosynaptic facilitation of mechanical nociceptive input in humans.

scholarly journals The Effects of Curare in the Cockroach

1970 ◽  
Vol 52 (3) ◽  
pp. 593-601
Author(s):  
K. J. FRIEDMAN ◽  
A. D. CARLSON
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Electrical Stimulation ◽  
Action Potential ◽  
Nerve Cord ◽  
Action Potentials ◽  
Periplaneta Americana ◽  
Sensory Motor ◽  
Giant Fibres ◽  
Stimulation Of

1. The study of insect curarization in the cockroach, Periplaneta americana, has been continued. The application of curare solution (0.032 M dTC) to the nerve cord produced blockage of action-potential conduction in the giant fibres lying within the nerve cord. 2. The application of curare solution to the cerci prevented the recording of action potentials from the cercal nerves of the organism. Application of dTC to the cercal nerve-A6 region of the cockroach prevented giant fibres from responding to electrical stimulation of the cercal nerves. These results are interpreted as indicating that curare blocks the conduction of action potentials in the cercal nerve. 3. It is proposed that curare can induce blockage of conduction in sensory, motor and central nervous system fibres. It is further proposed that this blockage of conduction is the mechanism of insect curarization. 4. The results of previous reports concerned with insect curarization are re-interpreted in view of the proposal. Several of the conflicts in these reports are resolved by the proposal that blockage of conduction is the mechanism of insect curarization.

Effects of different frequencies of stimulation of sciatic nerves on the patellar reflex

1959 ◽  
Vol 197 (3) ◽  
pp. 544-546 ◽  
Author(s):  
Salvatore De Salva ◽  
Y. T. Oester
Keyword(s):  
Electrical Stimulation ◽  
Sciatic Nerve ◽  
Nerve Stimulation ◽  
Spinal Section ◽  
Sciatic Nerves ◽  
Sciatic Nerve Stimulation ◽  
High Cervical ◽  
Frequency Of Stimulation ◽  
Reflex Stimulation ◽  
Stimulation Of

The patellar reflex was recorded every 10 seconds in cats under high cervical spinal section. The effects of different frequencies of electrical stimulation on both the ipsilateral and contralateral sciatic nerves were studied. At frequencies of 1–10/sec., contralateral sciatic nerve stimulation produced a depression of the patellar reflex. Frequencies of 20–120/sec. produced augmentation of the reflex. Stimulation of the ipsilateral sciatic nerve, through the same range of frequencies, only produced a gradient depression of the patellar reflex. The effect of pentobarbital on these reflexes in the same type of high cervical spinal cat was noted. The effects of frequency of stimulation, as well as anesthetic used, must be considered in using this reflex preparation.

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