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Urethane dose‐dependently inhibits genioglossal long‐term facilitation in un‐paralyzed anesthetized rats
Author(s) -
Cao Ying,
Liu Chun,
Ling Liming
Publication year - 2010
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.24.1_supplement.799.10
Subject(s) - chemistry , anesthesia , chloralose , medicine , cats
For 3 decades, urethane has been successfully used as an anesthetic in numerous long‐term facilitation (LTF) studies in several species of animals, which were anesthetized, paralyzed, vagotomized and artificially ventilated. However, acute intermittent hypoxia (AIH) failed to induce LTF in a study using urethane‐anesthetized spontaneously breathing rats. But LTF was observed in spontaneously breathing animals when urethane was totally or partly replaced by other anesthetics. The objective of this study was to test whether urethane inhibits AIH‐induced LTF in un‐paralyzed rats under normocapnia, and if yes, whether reducing urethane dose can restore LTF. Three groups of adult male Sprague‐Dawley rats were anesthetized (Group 1: 1.6 mg/kg urethane; Group 2: 50 mg/kg α‐chloralose + 0.9–1.2 mg/kg urethane; Group 3: 0.9 mg/kg urethane + 200–400 μg/kg/min alphaxalone), vagotomized and ventilated. Integrated genioglossal activity was measured before, during and after AIH (5 episodes of 3‐min isocapnic 12% O 2 with 3‐min 50% O 2 intervals). The AIH‐induced genioglossal LTF was absent in Group 1 rats (success rate was only ~1/7), but the LTF was present in Group 2 (in 8/10 rats) and Group 3 (in 10/10) rats. The hypoxic genioglossal response was not different among the 3 groups. These data demonstrated that urethane inhibits LTF in un‐paralyzed anesthetized rats in a dose‐dependent way. (Supported by NIH HL64912)