Disease relevance of Phrenic Nerve

• Unexpected right phrenic nerve injury during 5-fluorouracil continuous infusion plus cisplatin and vinorelbine in breast cancer patients [1].
• Integrated phrenic nerve activity was measured in anaesthetized, vagotomized, neuromuscularly blocked and artificially ventilated rats before, during and after three episodes of 5 min isocapnic hypoxia (P(a,O2) = 30-45 mmHg), separated by 5 min hyperoxia (50% O2) [2].
• 5. In ventilated rats, bilateral microinjection into RVL of kynurenate, but not xanthurenate, abolished resting activity and chemoreflex excitation of phrenic nerve activity, whilst in spontaneously breathing rats, kynurenate microinjection into RVL produced apnea and silenced phrenic nerves [3].
• The amplitude of respiratory sinus arrhythmia was attenuated (64 +/- 15%) by bupivacaine without affecting activity recorded from the phrenic nerve [4].
• Intravenous administration of the 5-HT(2A/2C)-receptor agonist (+/-)-2,5-dimethoxy-4-iodoamphetamine hydrochloride (DOI) induced respiratory-related activity in the phrenic nerve ipsilateral to hemisection under conditions in which CO(2) was maintained at constant levels and augmented the activity induced under conditions of hypercapnia [5].

High impact information on Phrenic Nerve

• We evaluated the contractile function of the diaphragm in well-nourished patients with stable COPD, using supramaximal, bilateral phrenic-nerve stimulation, which provides information about the strength and inspiratory action of the diaphragm [6].
• In four subjects, pressure was also measured during stimulation of the phrenic nerve at various frequencies before and after diaphragmatic fatigue was produced by resistive breathing, with and without aminophylline infusion [7].
• Moreover, morphological manifestations, such as loss of motor axons in the phrenic nerve and degeneration of facial motor neurons, were greatly reduced by CNTF, although the treatment did not start until the first symptoms of the disease had already become apparent and substantial degenerative changes were already present [8].
• Release of acetylcholinesterase from rat hemidiaphragm preparations stimulated through the phrenic nerve [9].
• CT-1-treated pmn mice showed a significantly reduced degeneration of facial motoneuron cytons and phrenic nerve myelinated axons [10].

Chemical compound and disease context of Phrenic Nerve

• Dose-dependent effects of halothane on the phrenic nerve responses to acute hypoxia in vagotomized dogs [11].
• Application of GABA (0.017-4.05 mg) to the intermediate area produced a dose-related inhibition of respiratory activity in the recurrent laryngeal nerve, as well as the phrenic nerve, that culminated in apnea [12].
• Phrenic nerve responses to hypoxia and CO2 in decerebrate dogs [13].
• Vecuronium-induced depression of phrenic nerve activity during hypoxia in the rabbit [14].
• The results suggested that cartap might cause the influx of extracellular Ca(2+) and the release of internal Ca(2+), with subsequent induction of muscular contracture in the isolated mouse phrenic nerve diaphragm [15].

Biological context of Phrenic Nerve

• The measured accumulation of AChE activity at a ligature on the phrenic nerve indicated that axonal transport contributed trivially to this turnover [16].
• 3. "Spontaneously' active neurones (n = 29) displayed a largely irregular pattern of firing, with no clear relationship between the level of the membrane potential and cycles of phrenic nerve activity at end-tidal CO2 < 5.0% [17].
• 4. Both the direct facilitatory effects of raphe obscurus stimulation on phrenic nerve activity and the long-term potentiation of respiration following the stimulus were prevented by pre-treating cats with methysergide, a serotonin receptor antagonist [18].
• PDI obtained during unilateral and bilateral phrenic nerve stimulation at 1 Hz (twitch PDI) at functional residual capacity (FRC) and during maximal sniff manoeuvres (sniff PDI) at various levels of inspiratory vital capacity (VCin) served as parameters for diaphragmatic strength [19].
• 2. Microinjections of glutamate (2.5 nmol) caused decreases in blood pressure, heart rate and phrenic nerve activity [20].

Anatomical context of Phrenic Nerve

• Stimulation of the phrenic nerve as a complication of vagus nerve pacing in a patient with epilepsy [21].
• Effects of electrical stimulation of the ipsilateral phrenic nerve above the heart were determined on cells in the C1-C2 spinal cord segments of 27 rats anesthetized with pentobarbital [22].
• 1. Repeated carotid sinus nerve (CSN) stimulation evokes a serotonin-dependent long-term facilitation (LTF) of phrenic nerve activity in cats [23].
• 4. Systemic injection of the A1 adenosine receptor antagonist 8-cyclopentyl-1,3-dipropylxanthine (DPCPX; 0.01-0.05 mg kg-1) resulted in an increase in mean peak phrenic nerve activity when arterial chemoreceptors were denervated [24].
• 1. Motoneurone synchronization was measured by cross-correlation between paired inspiratory discharges in external and internal intercostal nerves or their intramuscular branches (T3 to T8) or in the phrenic nerve (C5 root or both C5 and C6 roots independently) in anaesthetized, paralysed cats [25].

Associations of Phrenic Nerve with chemical compounds

• Reflex effects of aerosolized histamine on phrenic nerve activity [26].
• K, or electrical stimulation of the phrenic nerve, depletes both the vesicular and extravesicular pools of ACh when hemicholinium no [27].
• Repeated doses of progesterone (from 0.1 to 2.0 micrograms/kg, cumulative) caused a sustained (greater than 45 min) facilitation of phrenic nerve activity in female and male cats; however, the response was much more variable in females [28].
• The maximal response was obtained from the ventral part of RO and consisted of early and delayed excitatory responses that were of equal magnitude in both left and right C5 phrenic nerve roots [29].
• There was no change in spontaneous phrenic nerve discharge in response to injections of equivalent or larger volumes of saline or lidocaine [30].

Gene context of Phrenic Nerve

• The central band of acetylcholine receptor (AChR) clusters is also wider in Cdk5-/- diaphragms, together with the absence of S100 immunoreactivity along the phrenic nerve during late embryonic stages [31].
• In mice lacking Phr1, the phrenic nerve failed to completely innervate the diaphragm [32].
• Peptides derived from the luminal domain of synaptotagmin I and II are capable of blocking the neurotoxicity of BoNT/G in phrenic nerve preparations [33].
• Unlike previous observations suggesting that a dying-back process may be occurring in the mouse model of the disease, we did not observe differences between proximal and distal axon loss in phrenic nerves of SOD1 rats [34].
• Twitch tension of isolated phrenic nerve-diaphragm preparations elicited by electrical stimulations to the phrenic nerve was recorded isometrically, and the preparations were exposed to the purified enterotoxin [35].

Analytical, diagnostic and therapeutic context of Phrenic Nerve

• In addition, before and after histamine, phrenic nerve activity was recorded for single bursts during which the ventilator was switched off [26].
• Mechanical ventilation increases substance P concentration in the vagus, sympathetic, and phrenic nerves [36].
• 2. Bilateral microinjection of suramin (50 nl, 0.02 M), a P2 purinoceptor antagonist, into the retrofacial area in the artificially ventilated rat reduced resting phrenic nerve discharge [37].
• 1. The response of the diaphragm to both transcranial magnetic stimulation and electrical phrenic nerve stimulation was studied in thirteen normal subjects under conditions of either a 'reflex' drive to ventilation with inhaled CO2 or during volitional ventilation of similar magnitude [38].
• The effects of ketamine on renal sympathetic nerve activity and phrenic nerve activity in rabbits (with vagotomy) with and without afferent inputs from peripheral receptors [39].

References