KISEP Head and Neck Korean J Otolaryngol 1999;42:1547-54 강아지의후두화학반사에대한실험적연구 박한규 김광문 홍원표 김영호 김명상 김동영 Experimental Study of Laryngeal Chemoreflex in Puppies Han Q Park, MD, Kwang-Moon Kim, MD, Won Pyo Hong, MD, Young-Ho Kim, MD, Myung Sang Kim, MD and Dong Young Kim, MD Department of Otorhinolaryngology, Yonsei University College of Medicine, Seoul, Korea ABSTRACT Background and ObjectivesMechanical or chemical stimulation of the supraglottic mucosa may result in either or both of two responses: the laryngeal adductor reflex response LAR, which causes glottic closure, and the laryngeal chemoreflex LCR, which results in centrally mediated apnea, hemodynamic instability and swallowing. Exaggeration of this normally protective reflexes is thought to be responsible for several disorders, including the sudden infant death syndrome SIDS. Material and MethodsThe supraglottic laryngeal mucosa which was topically stimulated by saline, distilled water, cow's milk and acid at ph 1.0 was introduced in 14 anesthetized puppies of three different age groups. In group, four puppies were 2-weeks-of-age, and in group and, five puppies were 4 and 6-weeks-of-age, respectively. Result1 Strong acid ph 1.0 induced the LCR response. 2 After stimulating, respiration was depressed initially, followed by later hyperventilation. We found strong contraction or laryngospasm of thyroarytenoid TA muscle after a short period of latency. 3 Respiration was not, or minimally depressed in group. Moderate depression or apnea was elicited in group and. 4 After stimulating, the heart rate was reduced, but it had no statistical meaning. 5 We found 3 types of TA muscle contraction pattern. Type showed no laryngospasm, but large contraction wave was noted by EMG. Type showed no laryngospasm, but strong contraction was noted initially and followed by some large waves by EMG. Type showed laryngospasm that was visible to the naked eye and by EMG. 6 Peak to peak amplitude differences of TA muscle were significantly increased statistically in all age groups. ConclusionWe suggest that the LCR is an age-dependent response which is absent in very young puppies before 2 weeks and appears after that age. Thus, it has important implications that postnatal neural maturation may influence laryngeal reflex to some extent. Korean J Otolaryngol 1999;42:1547-54 KEY WORDSLaryngeal chemoreflex Laryngeal adductor reflex response Superior laryngeal nerve Postnatal neural maturation. 1547
1548 Fig. 1. Laryngeal preparation for the laryngeal chemoreflex in puppy. Thyroid cartilage was retracted and bipolar, concentric needle electrode was inserted into thyroarytenoid muscle. Korean J Otolaryngol 1999;42:1547-54
Fig. 2. Polygraph tracing of responses to acid at ph 1.0 in a case of 2 weeks of age. A Respiration tracing, B TA muscle EMG tracing type, C Heart beat tracing. The arrow shows the acid stimulation point. 1549
Fig. 3. Polygraphic tracng of responses to acid at ph 1.0 in a case of 4 week of age. ARespiration tracing, BTA muscle EMG tracing type, C Heart beat tracing. The arrow shows the acid stimulation point. Fig. 4. Polygraph tracing of responses to acid at ph 1.0 in a case of 6 weeks of age. ARespiration tracing, BTA muscle EMG tracing type, C Heart beat tracing. The arrow shows the acid stimulation point Table 1. Respiration changes immediate after stimulating the laryngeal mucosa with acid Apnea Respiration depression 5sec 2 weeks n 8 0 0 8 4 weeks n 9 4 5 0 6 weeks n10 3 7 0 Table 2. Respiration changes after the respiratory depression after stimulating the laryngeal mucosa with acid Pre times/min Post times/min p value 2 weeks n 8 40.52.1* 69.5 3.3 0.011 4 weeks n 9 34.10.7 68.4 3.2 0.008 6 weeks n10 31.51.8 66.915.5 0.005 *Averagestandard deviation 1550 Korean J Otolaryngol 1999;42:1547-54
Table 3. Heart rate changes after stimulating the laryngeal mucosa with acid Pre beats/min Post beats/min p value 2 weeks n 8 196.06.8 186.48.5 0.18 4 weeks n 9 185.37.0 182.69.9 0.35 6 weeks n10 151.84.9 142.44.7 0.07 Table 4. Types of TA muscle contraction after stimulating the laryngeal mucosa with acid Type Type Type 2 weeks n 8 5 3 0 4 weeks n 9 2 6 1 6 weeks n10 0 2 8 Table 5. Peak to peak amplitude difference of TA muscle after stimulating the laryngeal mucosa with acid Pre mv Post mv p value 2 weeks n 8 125.043.6 2160.0511.0 * 4 weeks n 9 75.615.8 1285.7795.0 0.018 6 weeks n10 74.413.3 1030.0667.1 0.005 *Exist in only 3 cases 1551
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