Search results for "Phrenic Nerve"
showing 10 items of 29 documents
Diaphragmatic paralysis following minor cervical trauma.
2007
Two asthmatic patients developed unilateral diaphragmatic paralysis from phrenic nerve injury, in one case following cervical chiropractic manipulation and in the other after a motorcycle accident. Both presented with increased dyspnea and orthopnea. Diagnosis, severity, and level of the lesion were established by neurophysiological methods, which are preferred to chest radiography and diaphragmatic ultrasonography. In spite of only partial electrophysiological recovery of the nerve, both patients were asymptomatic 1 year later.
High volume and low concentration of anaesthetic solution in the perivascular interscalene sheath determines quality of block and incidence of compli…
2006
Background and objective: In the perivascular sheath of the brachial plexus, the volume of anaesthetic solution determines the quality of anaesthetic cover. Fibrous septa may divide the perivascular space into compartments, leading to inadequate diffusion of the anaesthetic solution. The aim of our study was to obtain good anaesthesia and less complications using high volume of low concentration anaesthetic solution, overcoming the obstacle of the septa with a double approach to the scalene sheath. Methods: Sixty patients scheduled for shoulder capsuloplasty received both Winnie interscalene brachial plexus block and Pippa proximal cranial needle approach. The patients were randomly assigne…
GABA, receptor mediated fast synaptic inhibition in the rabbit brain-stem respiratory system
1991
The involvement of GABA mediated neurotransmission in the central control of respiration was investigated by administration of the specific GABAA receptor agonist muscimol and the specific GABAA receptor antagonist biculline into the fourth cerebral ventricle of the rabbit. Cycle-triggered averaging of the phrenic nerve activity (PNA) was used to quantify drug-induced changes of the central respiratory pattern. Muscimol reduced the peak amplitude of PNA and increased the duration of the respiratory phases. High amounts of muscimol led to a long-lasting but reversible central apnea. Bicuculline very effectively blocked the effects of externally applied muscimol. Blockade of intrinsically act…
Backfiring of the isolated rat phrenic nerve does not collide with impulse propagation following repetitive nerve stimulation at 1-50 Hz.
1991
Acetylcholinesterase inhibition with neostigmine in the isolated rat phrenic nerve-hemidiaphragm preparation induced axonal backfiring and repetitive compound muscle action potentials following single nerve stimulation. The duration of backfiring and the repetitive compound muscle action potentials did not exceed 55 ms. With repetitive nerve stimulation at frequencies ranging from 1 to 50 Hz, backfiring was present only with the first stimulus and the amplitude of the second compound muscle action potential was maximally reduced, while the subsequent responses recovered gradually. However, the amplitudes of the concommitant antidromic nerve action potentials remained unchanged during the en…
STIMULATION OF ?1-ADRENOCEPTORS ENHANCES ELECTRICALLY EVOKED [3H]-ACETYLCHOLINE RELEASE FROM RAT PHRENIC NERVE
1990
1. The effects of isoprenaline, noradrenaline and fenoterol on the electrically evoked release of [3H]-acetylcholine from the rat phrenic nerve were investigated. 2. Isoprenaline (0.1 mumol/L) and noradrenaline (1 mumol/L) enhanced evoked [3H]-acetylcholine release by about 90%, an effect which was abolished by CGP 20712A (0.1 mumol/L), a specific antagonist at beta 1-adrenoceptors. Noradrenaline still enhanced [3H]-acetylcholine release in the presence of phentolamine (1 mumol/L). 3. The enhancing effect of both isoprenaline and noradrenaline decreased at prolonged exposure times (24-32 min). A pre-exposure of the tissue to a low concentration (0.01 mumol/L) of isoprenaline prevented the e…
Release of [3H]acetylcholine from a modified rat phrenic nerve-hemidiaphragm preparation
1986
Two different preparations of the rat phrenic nerve-hemidiaphragm (whole nerve-muscle preparation, end-plate preparation) were used for studying synthesis and release of radioactive acetylcholine in the absence and presence of cholinesterase inhibitors. When the whole nerve-muscle preparation (110-180 mg) was incubated with [3H]choline, only small amounts of radioactive acetylcholine were synthesized within the tissue. Electrical nerve stimulation of the whole nerve-muscle preparation produced no increase in tritium outflow. Incubation of the end-plate preparation (16-29 mg) which was obtained after removal of most of the muscle mass led to the formation of large amounts of [3H]acetylcholin…
alpha-Bungarotoxin, kappa-bungarotoxin, alpha-cobratoxin and erabutoxin-b do not affect [3H]acetylcholine release from the rat isolated left hemidiap…
1995
Endplate preparations of the rat left hemidiaphragm were incubated with [3H]choline to label neuronal transmitter stores. Nerve evoked release of newly-synthesized [3H]acetylcholine was measured in the absence of cholinesterase inhibitors to investigate whether snake venom neurotoxins by blocking presynaptic nicotinic autoreceptors affect evoked transmitter release. Contractions of the indirectly stimulated hemidiaphragm were recorded to characterize the blocking effect of alpha-neurotoxins at the post-synaptic nicotinic receptors. Neither the long chain neurotoxins alpha-cobratoxin (1 microgram ml-1) and alpha-bungarotoxin (5 microgram ml-1) nor the short chain neurotoxin erabutoxin-b (0.1…
Influence of rubrospinal tract and the adjacent mesencephalic reticular formation on the activity of medullary respiratory neurons and the phrenic ne…
1988
Suprapontine brain sites acting on the central respiratory system have been demonstrated to give rise to inspiratory as well as expiratory facilitatory effects. In the present study the inspiratory inhibitory effect which has been reported in the cat to be elicited consistently by electrical stimulation of the rubrospinal tract and the adjacent mesencephalic reticular formation was examined in the urethane-anaesthetized rabbit. Stimulation of these sites with single electrical shocks of moderate intensity induced a short latency (onset after 3.0 ms) transient (duration: 29 ms) inhibition of the phrenic nerve activity (PHR). Short volleys of stimuli applied in mid- to late-inspiration led to…
Uptake and metabolism of [3H]choline by the rat phrenic nerve-hemidiaphragm preparation
1987
A whole nerve-muscle preparation (about 160 mg) or an end-plate preparation (about 25 mg) of the rat phrenic nerve-hemidiaphragm were incubated with [3H]choline, to investigate choline uptake and choline metabolism. Choline uptake was measured from the disappearance of choline from the incubation medium during the loading period and from the retention of tritium in the tissue after the loading and washout period. Based on the results obtained with both methods the end-plate preparation takes up three times as much choline than the whole nerve-muscle preparation or a small muscle strip that was cut outside the end-plate region and had a similar size as the end-plate preparation. Choline upta…
Presynaptic nicotine receptors mediating a positive feed-back on transmitter release from the rat phrenic nerve.
1986
The effects of 1,1-dimethyl-4-phenylpiperazinium (DMPP) and of nicotine receptor antagonists on [3H]acetylcholine release from the rat phrenic nerve preincubated with [3H]choline were investigated in the absence and presence of cholinesterase inhibitors (presynaptic effects). Additionally, the effects of hexamethonium and tubocurarine on the muscle contraction of the indirectly stimulated diaphragm were examined (postsynaptic effects). DMPP (1-30 microM) increased (76-92%), whereas hexamethonium (0.001-1 mM) and tubocurarine (1-10 microM) decreased (52-60%) the release of [3H]acetylcholine following a train of 100 pulses at 5 Hz. The release caused by a longer train (750 pulses at 5 Hz) was…