COMPLETE INHIBITION OF ADRENOCORTICAL RESPONSES FOLLOWING SCIATIC NERVE STIMULATION IN RATS WITH HYPOTHALAMIC ISLANDS

1975 ◽  
Vol 78 (3) ◽  
pp. 539-544 ◽  
Author(s):  
Shaul Feldman ◽  
Nisim Conforti ◽  
Israel Chowers
Keyword(s):  
Sciatic Nerve ◽  
Nerve Stimulation ◽  
Acoustic Stimulation ◽  
Plasma Corticosterone ◽  
Neural Pathways ◽  
Implanted Electrodes ◽  
Sciatic Nerve Stimulation ◽  
Adrenocortical Responses ◽  
Pentobarbital Anaesthesia ◽  
Intact Rats

ABSTRACT Previous studies from this laboratory have demonstrated that in rats with hypothalamic islands the adrenocortical response to photic and acoustic stimulation was partially inhibited indicating that they were at least to a certain degree neurally mediated, though ether stress produced normal adrenocortical responses. With the purpose of determining to what extent afferent somatosensory connections to the hypothalamus participate in the activation of adrenocortical responses following sciatic nerve stimulation, the effects of this stimulus applied through chronically implanted electrodes were studied on the plasma corticosterone levels in pentobarbital anaesthetized intact animals and in rats with hypothalamic islands. Ether stress or sciatic nerve stimulation for 2 min in intact rats produced a rise of plasma corticosterone to 32.1 ± 1.2 and 32.1 ± 1.8 μg/100 ml, respectively. However, in animals with hypothalamic islands the corresponding values were 29.2 ± 1.8 and 12.4 ± 0.8 μg/100 ml, respectively. The latter value was not significantly different from the basal corticosterone levels (13.0 ± 1.2 μg/100 ml) found in rats 15 min after pentobarbital anaesthesia, the time when the sciatic stimulus was applied. The present data indicate that the adrenocortical discharge following sciatic nerve stimulation is completely inhibited by hypothalamic deafferentation and therefore depends entirely on the activation of the afferent neural pathways to the hypothalamus.

ADRENOCORTICAL RESPONSES FOLLOWING SCIATIC NERVE STIMULATION IN RATS WITH PARTIAL HYPOTHALAMIC DEAFFERENTATIONS

1975 ◽  
Vol 80 (4) ◽  
pp. 625-629 ◽  
Author(s):  
Shaul Feldman ◽  
Nissim Conforti ◽  
Israel Chowers
Keyword(s):  
Sciatic Nerve ◽  
Nerve Stimulation ◽  
Neural Pathways ◽  
Mediobasal Hypothalamus ◽  
Adrenocortical Response ◽  
Sciatic Nerve Stimulation ◽  
Adrenocortical Responses ◽  
Intact Rats

ABSTRACT Studies from this laboratory have demonstrated that the adrenocortical response following sciatic nerve stimulation is completely inhibited in rats with hypothalamic islands, indicating that this response depends entirely on the activation of afferent neural pathways to the hypothalamus. With the purpose of identifying the site of entry of these neural pathways into the mediobasal hypothalamus the effects of partial hypothalamic deafferentations were studied. It was found that in rats with posterior or posterolateral deafferentation the adrenocortical responses were similar to those obtained in intact rats, while anterior and anterolateral deafferentation resulted in a reduction of 62.3 and 53.3 %, respectively. These results would indicate that the sciatic impulses which activate the adrenocortical response involve neural afferents which enter the mediobasal hypothalamus by an anterior pathway.

THE ROLE OF THE MEDIAL FOREBRAIN BUNDLE IN MEDIATING ADRENOCORTICAL RESPONSES TO NEUROGENIC STIMULI

1971 ◽  
Vol 51 (4) ◽  
pp. 745-749 ◽  
Author(s):  
S. FELDMAN ◽  
N. CONFORTI ◽  
I. CHOWERS
Keyword(s):  
Medial Forebrain Bundle ◽  
Acoustic Stimulation ◽  
Plasma Corticosterone ◽  
Neural Pathways ◽  
Afferent Pathway ◽  
Lower Plasma ◽  
Bilateral Lesions ◽  
Adrenocortical Responses ◽  
Intact Rats

SUMMARY The effects of ether stress and of photic and acoustic stimulation on adrenocortical responses were studied in normal rats and in rats with bilateral lesions in the medial forebrain bundle (MFB). While the response to ether stress was slightly reduced, the neurogenic stimuli produced much lower plasma corticosterone levels in the lesioned animals compared with intact rats. The neural pathways and the role of the MFB in mediating adrenocortical responses to neurogenic stimuli are discussed. The present results demonstrate that the MFB is the main final afferent pathway through which neural impulses to the hypothalamus are propagated, thus activating the secretion of adrenocorticotrophin.

Multiple response to photic stimulation in cats

1959 ◽  
Vol 197 (6) ◽  
pp. 1233-1236 ◽  
Author(s):  
T. Corwin Fleming ◽  
Edward V. Evarts
Keyword(s):  
Sciatic Nerve ◽  
Nerve Stimulation ◽  
Cortical Response ◽  
Photic Stimulation ◽  
Secondary Response ◽  
Multiple Response ◽  
Natural Sleep ◽  
Implanted Electrodes ◽  
Photic Stimulus ◽  
Sciatic Nerve Stimulation

This study was carried out in order to compare the multiple cortical response to a photic stimulus and the secondary response to sciatic nerve stimulation. Late responses to flash and to sciatic nerve shock were recorded in acute cat preparations anesthetized with pentobarbital. The responses to the two types of stimuli differed in distribution (visual multiple response confined to primary receiving area, sciatic secondary generalized), form and anesthetic level optimal for their production (deeper anesthesia for the sciatic secondary than for the visual multiple response). In cats with chronically implanted electrodes, it was found that the multiple response to flash was present during natural sleep and was abolished by arousal.

scholarly journals An investigation of arterial insufficiency in the rat hindlimb Correlation of skeletal muscle bloodflow and glucose utilization in vivo

1986 ◽  
Vol 240 (2) ◽  
pp. 395-401 ◽  
Author(s):  
R A Challiss ◽  
D J Hayes ◽  
G K Radda
Keyword(s):  
Skeletal Muscle ◽  
Sciatic Nerve ◽  
Glucose Uptake ◽  
Nerve Stimulation ◽  
Linear Correlation ◽  
Glucose Utilization ◽  
Fold Increase ◽  
Artery Ligation ◽  
Sciatic Nerve Stimulation

Muscle bloodflow and the rate of glucose uptake and phosphorylation were measured in vivo in rats 7 days after unilateral femoral artery ligation and section. Bloodflow was determined by using radiolabelled microspheres. At rest, bloodflow to the gastrocnemius, plantaris and soleus muscles of the ligated limb was similar to their respective mean contralateral control values; however, bilateral sciatic nerve stimulation at 1 Hz caused a less pronounced hyperaemic response in the muscles of the ligated limb, being 59, 63 and 49% of their mean control values in the gastrocnemius, plantaris and soleus muscles respectively. The rate of glucose utilization was determined by using the 2-deoxy[3H]glucose method [Ferré, Leturque, Burnol, Penicaud & Girard (1985) Biochem. J. 228, 103-110]. At rest, the rate of glucose uptake and phosphorylation was statistically significantly increased in the gastrocnemius and soleus muscles of the ligated limb, being 126 and 140% of the mean control values respectively. Bilateral sciatic nerve stimulation at 1 Hz caused a 3-5-fold increase in the rate of glucose utilization by the ligated and contralateral control limbs; furthermore, the rate of glucose utilization was significantly increased in the muscles of the ligated limb, being 140, 129 and 207% of their mean control values respectively. For the range of bloodflow to normally perfused skeletal muscle at rest or during isometric contraction determined in the present study, a linear correlation between the rate of glucose utilization and bloodflow can be demonstrated. Applying similar methods of regression analysis to glucose utilization and bloodflow to muscles of the ligated limb reveals a similar linear correlation. However, the rate of glucose utilization at a given bloodflow is increased in muscles of the ligated limb, indicating an adaptation of skeletal muscle to hypoperfusion.

scholarly journals Electroacupuncture Reduces the Effects of Acute Noxious Stimulation on the Electrical Activity of Pain-Related Neurons in the Hippocampus of Control and Neuropathic Pain Rats

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Jun-Ying Wang ◽  
Renbo Chen ◽  
Shu-Ping Chen ◽  
Yong-Hui Gao ◽  
Jian-Liang Zhang ◽  
...  
Keyword(s):  
Sciatic Nerve ◽  
Electrical Activity ◽  
Nerve Stimulation ◽  
Mek Inhibitor ◽  
Mitogen Activated Protein Kinase ◽  
Noxious Stimulation ◽  
Ca1 Region ◽  
Mitogen Activated Protein ◽  
Hippocampal Area ◽  
Sciatic Nerve Stimulation

To study the effects of acupuncture analgesia on the hippocampus, we observed the effects of electroacupuncture (EA) and mitogen-activated protein kinase (MEK) inhibitor on pain-excited neurons (PENs) and pain-inhibited neurons (PINs) in the hippocampal area CA1 of sham or chronic constrictive injury (CCI) rats. The animals were randomly divided into a control, a CCI, and a U0126 (MEK1/2 inhibitor) group. In all experiments, we briefly (10-second duration) stimulated the sciatic nerve electrically and recorded the firing rates of PENs and PINs. The results showed that in both sham and CCI rats brief sciatic nerve stimulation significantly increased the electrical activity of PENs and markedly decreased the electrical activity of PINs. These effects were significantly greater in CCI rats compared to sham rats. EA treatment reduced the effects of the noxious stimulus on PENs and PINs in both sham and CCI rats. The effects of EA treatment could be inhibited by U0126 in sham-operated rats. The results suggest that EA reduces effects of acute sciatic nerve stimulation on PENs and PINs in the CA1 region of the hippocampus of both sham and CCI rats and that the ERK (extracellular regulated kinase) signaling pathway is involved in the modulation of EA analgesia.

scholarly journals Sciatic nerve stimulation activates the retrotrapezoid nucleus in anesthetized rats

2016 ◽  
Vol 116 (5) ◽  
pp. 2081-2092 ◽  
Author(s):  
Roy Kanbar ◽  
Ruth L. Stornetta ◽  
Patrice G. Guyenet
Keyword(s):  
Sciatic Nerve ◽  
Nerve Stimulation ◽  
Motor Nucleus ◽  
Sprague Dawley ◽  
Neuron Firing ◽  
Afferent Stimulation ◽  
Retrotrapezoid Nucleus ◽  
Facial Motor Nucleus ◽  
Stimulation Experiments ◽  
Sciatic Nerve Stimulation

Retrotrapezoid nucleus (RTN) neurons sustain breathing automaticity. These neurons have chemoreceptor properties, but their firing is also regulated by multiple synaptic inputs of uncertain function. Here we test whether RTN neurons, like neighboring presympathetic neurons, are excited by somatic afferent stimulation. Experiments were performed in Inactin-anesthetized, bilaterally vagotomized, paralyzed, mechanically ventilated Sprague-Dawley rats. End-expiratory CO2 (eeCO2) was varied between 4% and 10% to modify rate and amplitude of phrenic nerve discharge (PND). RTN and presympathetic neurons were recorded extracellularly below the facial motor nucleus with established criteria. Sciatic nerve stimulation (SNstim, 1 ms, 0.5 Hz) slightly increased blood pressure (6.6 ± 1.6 mmHg) and heart rate and, at low eeCO2 (<5.5%), entrained PND. Ipsi- and contralateral SNstim produced the known biphasic activation of presympathetic neurons. SNstim evoked a similar but weaker biphasic response in up to 67% of RTN neurons and monophasic excitation in the rest. At low eeCO2, RTN neurons were silent and responded more weakly to SNstim than at high eeCO2. RTN neuron firing was respiratory modulated to various degrees. The phasic activation of RTN neurons elicited by SNstim was virtually unchanged at high eeCO2 when PND entrainment to the stimulus was disrupted. Thus RTN neuron response to SNstim did not result from entrainment to the central pattern generator. Overall, SNstim shifted the relationship between RTN firing and eeCO2 upward. In conclusion, somatic afferent stimulation increases RTN neuron firing probability without altering their response to CO2. This pathway may contribute to the hyperpnea triggered by nociception, exercise (muscle metabotropic reflex), or hyperthermia.

EFFECTS OF PARTIAL HYPOTHALAMIC DEAFFERENTATIONS ON ADRENOCORTICAL RESPONSES

1972 ◽  
Vol 69 (3) ◽  
pp. 526-530 ◽  
Author(s):  
S. Feldman ◽  
N. Conforti ◽  
I. Chowers
Keyword(s):  
Medial Forebrain Bundle ◽  
Acoustic Stimulation ◽  
Sensory Inputs ◽  
Adrenocortical Responses ◽  
Intact Rats

ABSTRACT The effects of ether stress and photic and acoustic stimulation on adrenocortical responses were studied in normal rats and in three groups of animals with partial hypothalamic anterior, anterolateral and posterolateral deafferentations, respectively. Animals with anterior deafferentation only, show the same responses as the intact rats, while in the two other groups the response to ether was normal, but that to photic and acoustic stimulation was significantly inhibited. These data would indicate that the transmission of impulses in the medial forebrain bundle and possibly posterior sensory inputs to the hypothalamus play an important role in the adrenocortical responses following neurogenic stimulation.

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