Habituation and dehabituation of the spinal polysynaptic reflex responses: Modification by naloxone and opiates and their anatomical correlates

Fernández-Guardiola, Augusto; Pellicer, Francisco; León-Olea, Martha; Asai, Miguel; Sánchez-Álvarez, Marcela

doi:10.1016/0143-4179(89)90068-1

Cited by 5 publications

(2 citation statements)

References 22 publications

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“…Elevated levels of {:l-endorphins have also been documented in the cerebrospinal fluid of infants with central apnea (I I). Furtherm ore, endogenous opiates have been shown to playa major role in causing the response decrement after repeated application ofa numb er of stimuli such as pain-evoked potentials in response to repeated stimulation of dental pulp in rabbits (14), of polysynaptic reflexes in the spinal cord of decerebrate cats in response to peripheral nerve stimulation (15), and of evoked potent ials recorded from the reticular formation of the brain in frogs in response to peripheral nerve stimulation (25). These data taken together with the evidence for accumulation of opiates during hypoxia in young animal s suggested that endogenous opiates ma y be responsible for causing the arousal response decrement after repeated exposure to hypoxemia durin g sleep.…”

Section: Discussionmentioning

confidence: 99%

“…Elevated levels of (3-endorphins have also been documented in the cerebro spinal fluid of infants with central apnea (11). Furtherm ore, endogenous opiates have been shown to play a major role in causing the response decrem ent after repeated application of a number of stimuli such as pain-evoked potentials in respon se to repeated stimulation of dental pulp in rabbits ( 14) and of polysynaptic reflexes in the spinal cord of decerebrate cats in response to peripheral nerve stimulat ion (15). With this in mind , we have done experiments to test the hypothesis that end ogenous opiates playa major role in causing the arousal response decrement to hypoxemia in lambs.…”

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Naloxone Does Not Alter the Arousal Response Decrement after Repeated Exposure to Hypoxemia during Sleep in Lambs

Konduri

Fewell

1992

Pediatr Res

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Arousal is an important protective response that may prevent severe hypoxemia and death during sleep. Hypoxemia may occur during sleep in indi viduals with chronic lun g disease ( 1-3). Th e usual respirato ry respon se to hypoxemia is an increase in ventilat ion, which tends to increase the alveolar and arterial oxygen ten sion . However, the ventilatory response to hypoxemi a is decreased during active sleep compared to quiet sleep in som e species that develop rib cage collapse during active sleep [e.g. lambs (4) and calves (5)]. T hus, the arousal respon se is an im portant protective respon se when we consider the overa ll cardiorespiratory response to hypoxemi a during sleep (6-9).Experiments were done on five lambs ranging in age from 10 to 19 d. Each lamb was separated from its ewe 1 to 3 dafter birth and was hou sed in our laboratory in a Plexiglas cage with continu ous access to milk (Iamb milk replacer, Land O'Lakes, Inc., Fort Dodge , IA). Th e lambs were among oth er lambs, fed and slept ad libitum, and soon became accustomed to the surroundings and laboratory personnel.S urgical preparation. Each lamb underwent one operation before study. Before the operation, each lamb was given atropine sulfate (0.2 mg/kg s.c.) and ketamine HCl (10 mg/k g intramuscularly) and its trachea was intubated with a cuffed endotracheal tube. The cuff was inflated to a gas tight fit and anesthesia was ma intain ed by ventilating th e lamb's lungs with I to 3% isoflurane (Fo rane, Anaquest, Mad ison , WI) in oxygen and nitrous oxide (3: I). An ECG and rectal temp erature were monitored du ring surgery, and core temperature was kept near 39°C with a heat ing pad.The operation was don e between 7 and 16 d of age when a double-lumen fiberopti c catheter oximeter (model U440 opticath, Oximetrix, Inc ., Mountain View, CA) was inserted into the thoracic aorta via a femor al artery for continuous measurement of arterial Hb oxygen satu ration and systemic blood pressure. Electrodes for the following recordings were also implanted: electrocorticogram, electro oculogram , nuchal electromyogram , and diaphragm electromyogram . A reference wire was sutured int o the s.c. tissue of the scalp. The electrodes were made in our 222ABSTRACT. Experiments were done to determine if endogenous opiates cause the arousal response decrement that follows repeated exposure to hypoxemia during sleep in lambs. Five lambs were anesthetized and instrumented for sleep staging and measurement of arterial Hb oxygen saturation. No sooner than 3 d after surgery, measurements were made in quiet sleep and active sleep during control periods when the lambs were breathing 21% oxygen and during experimental periods when the lambs were breathing 5% oxygen. The experimental period was terminated during each epoch by changing the inspired gas mixture back to 21% oxygen, once the lamb aroused from sleep. After each lamb had been exposed to 5% oxygen during 100 consecutive epochs of sleep, naloxone-an opiate antagonist-was given i.v, in a dose of 3 mgJkg as a bolus. T...

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Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

Naloxone Does Not Alter the Arousal Response Decrement after Repeated Exposure to Hypoxemia during Sleep in Lambs

Konduri

Fewell

1992

Pediatr Res

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Non-nociceptive upper limb afferents modulate masseter muscle EMG activity in man

Deriu

Milia

et al. 2002

Exp Brain Res

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Recent electrophysiological data obtained in anaesthetized rats evidenced jaw muscle excitatory responses to the electrical stimulation of type II limb somatosensory afferents. In the present work, we describe an inhibitory reflex evoked in human masseter muscles by stimulation of non-nociceptive fibres travelling in the median and radial nerves (MED and RAD, respectively). Eighteen healthy volunteers participated in the study. Subjects were seated on a comfortable chair, with the complex head-mandible-neck-trunk and the limbs securely fixed to the chair. Attempts were made to minimize possible interferences due to the activation of afferents other than the stimulated ones. The subjects were instructed to contract masseter muscles at a submaximal level and to maintain a stable level of muscle contraction during all trials. EMG voluntary activity was recorded from both masseter muscles by means of coaxial needle electrodes before and after the electrical stimulation of MED and/or RAD at intensities below pain threshold. In all subjects, MED stimulation induced bilaterally a marked depression of masseter EMG activity, which occurred at a latency of 23.6 +/- 2.1 ms and lasted 27.8 +/- 6.6 ms. RAD stimulation also induced a marked reduction in masseter EMG activity, but this effect was clearly observed in 9 out of 18 subjects, and it showed latency (30.2 +/- 7.5 ms) and duration (44.9 +/- 5.4 ms) significantly longer in comparison with the MED-induced effect. All subjects exhibited the inhibitory period in masseter EMG following the simultaneous stimulation of both nerves; this one appeared at a latency not significantly different (25.3 +/- 5.9 ms) and lasted much more (37.4 +/ - 8.2 ms) than EMG depression evoked by MED stimulation. The duration of masseter muscle inhibition, induced by MED and/or RAD stimulation, was inversely related to the level of EMG activity, while latency was not related to it. Significant increases in the inhibitory period duration were also observed by increasing stimulus intensity, within a subthreshold range for the activation of nociceptive fibres. In all cases, the inhibitory period was followed by a later excitatory rebound activity, whose latency and duration depended on the duration of the preceding EMG inhibition and on the background level of masseter activation. In conclusion, results evidenced that the activation of arm somatosensory fibres modulates masseter muscle activity in normal man. This might lead to a coordination between limb and masticatory muscle activity, which is required in several complex motor acts.

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Synaptic interactions in a newly identified excitatory synapse ofHelix aspersa: concurrent enkephalinergic and GABAergic modulation

Gutiérrez

1994

Brain Research

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Habituation and dehabituation of the spinal polysynaptic reflex responses: Modification by naloxone and opiates and their anatomical correlates

Cited by 5 publications

References 22 publications

Naloxone Does Not Alter the Arousal Response Decrement after Repeated Exposure to Hypoxemia during Sleep in Lambs

Naloxone Does Not Alter the Arousal Response Decrement after Repeated Exposure to Hypoxemia during Sleep in Lambs

Non-nociceptive upper limb afferents modulate masseter muscle EMG activity in man

Synaptic interactions in a newly identified excitatory synapse ofHelix aspersa: concurrent enkephalinergic and GABAergic modulation

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