Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0010200 (cough)
 23,843 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have investigated the various sensory modalities represented in the laryngeal nerves of the guinea pig. In addition, we have examined the defensive responses to mechanical stimuli and capsaicin instillation into the laryngeal lumen of the same species. Recording from both the whole superior laryngeal nerve and from single units of the same nerve revealed the presence of afferent activity related (1) to the contraction of laryngeal muscles and/or the 'tracheal tug', (2) to transmural pressure changes, either positive or negative and (3) to mechanical and chemical irritants. The irritant type receptors of this species, when challenged with water solutions, show two distinct patterns of activation: some behave as osmoreceptors, some respond to the lack of chloride ions. Challenges with capsaicin solutions activated one ending with the characteristics of a C-fiber receptor that failed to respond to a subsequent trial. This behavior is consistent with the reflex apnea, dependent on an intact laryngeal innervation, induced by capsaicin instillation that was not elicitable on repeating the challenge. Cough to mechanical probing of the supraglottic area depended on an intact SLN, whereas cough elicited from the subglottic area depended on an intact RLN. Cough to mechanical stimulation could not be desensitized by capsaicin. These findings suggest the presence of two independent afferent pathways for defensive responses.
 ...
PMID:Laryngeal afferent activity and reflexes in the guinea pig. 178 Jun 1

Cough reflex is characterized by a large expulsive phase for expelling the mucus or particles from the airway. The present study investigated the involvement of N-methyl-D-aspartate (NMDA) mechanisms in the expulsive phase of cough reflex using decerebrate and paralyzed cats. A fictive cough was induced by repetitive stimulation of the superior laryngeal nerve, which was characterized by an increased inspiratory discharge in the phrenic nerve (the stage 1 of fictive cough; SC1) and large spindle-shaped discharge in the iliohypogastric nerve (the stage 2 of fictive cough; SC2). Intravenous injection of an antagonist of NMDA receptors, dizocilpine (0.1mg/kg), increased the threshold intensity of stimulation for inducing a fictive cough. The SC2 iliohypogastric response was more vulnerable to dizocilpine than the SC1 phrenic response. Membrane potential of augmenting expiratory (aug-E) neurons was recorded from the caudal ventral respiratory group. Aug-E neurons showed a large depolarization with a high frequency discharge during the SC2 in major cases (n=35) and hyperpolarization in minor cases (n=6). Dizocilpine inhibited the occurrence of these SC2 responses of aug-E neurons without any effect on the basal respiratory fluctuations of membrane potential. This drug had no significant effect on waves of excitatory and inhibitory postsynaptic potentials evoked in aug-E neurons by single pulse stimulation of the SLN. The present results demonstrated that NMDA mechanisms contribute preferentially to the expulsive phase response in aug-E neurons during fictive cough reflex.
 ...
PMID:N-methyl-D-aspartate mechanisms in depolarization of augmenting expiratory neurons during the expulsive phase of fictive cough in decerebrate cats. 1840 87

Injury to the bilateral internal branch of superior laryngeal nerve (ibSLN) brings on an impairment of the laryngeal cough reflex that could potentially result in aspiration pneumonia and other respiratory illnesses. We describe a patient with traumatic cervical injury who underwent bilateral ibSLN palsy after anterior cervical discectomy with fusion (ACDF). An 75-year-old man visited with cervical spine fracture and he underwent ACDF through a right side approach. During the post-operative days, he complained of high pitched tone defect, and occasional coughing during meals. With a suspicion of SLN injury and for the work up for the cause of aspiration, we performed several studies. According to the study results, he was diagnosed as right SLN and left ibSLN palsy. We managed him for protecting from silent aspiration. Swallowing study was repeated and no evidence of aspiration was found. The patient was discharged with incomplete recovery of a high pitched tone and improved state of neurologic status. The SLN is an important structure; therefore, spine surgeons need to be concerned and be cautious about SLN injury during high cervical neck dissection, especially around the level of C3-C4 and a suspicious condition of a contralateral nerve injury.
 ...
PMID:Bilateral internal superior laryngeal nerve palsy of traumatic cervical injury patient who presented as loss of cough reflex after anterior cervical discectomy with fusion. 2311 75