title: Evidence of nitric oxide in the exhaled gas of Asian elephants (Elephas maximus).
abstract: Nitric oxide (NO) produced in the respiratory tract is released into the respiratory gases of humans, rabbits, guinea-pigs, and rats. We analysed the NO concentrations in the exhaled gas of four awake Asian elephants. Two methods were employed: (1) exhaled gas was sampled from the elephants' trunks with a 1 L syringe and analysed for NO concentrations by chemiluminescence; (2) respiratory gas was continuously aspirated via a thin plastic tube positioned within the trunk and on-line analysed for NO concentrations by chemiluminescence. Syringe sampling (n = 4), when corrected for dilution by ambient air using linear regression analysis, revealed a mean NO concentration of 31 parts per billion (ppb); highest exhalatory concentrations measured during continuous suctioning were 27 and 28 ppb (n = 2). The exhaled NO concentrations in elephants are similar to those found in humans measured with a comparable technique. This supports the hypothesis that a size-independent 'normal value' of endogenous NO is provided in the airways which may contribute to regulation of pulmonary ventilation and perfusion by autoinhalation in some mammals.
authors.affiliation: Klinik für Anästhesiologie und operative Intensivmedizin, Virchow-Klinikum Medizinische Fakultät der Humboldt-Universität zu Berlin, Germany.
authors.forename: K
authors.initials: K
authors.lastname: Lewandowski
authors.forename: T
authors.initials: T
authors.lastname: Busch
authors.forename: M
authors.initials: M
authors.lastname: Lewandowski
authors.forename: U
authors.initials: U
authors.lastname: Keske
authors.forename: H
authors.initials: H
authors.lastname: Gerlach
authors.forename: K J
authors.initials: KJ
authors.lastname: Falke
mesh_terms: D000818:Animals; D002245:Carbon Dioxide / Q000032:analysis; D004606:Elephants / Q000502:physiology*; D005260:Female; D008163:Luminescent Measurements; D009569:Nitric Oxide / Q000032:analysis*; D012123:Pulmonary Ventilation / Q000502:physiology*; D012137:Respiratory System / Q000378:metabolism*; D013594:Syringes
chemical_list: D002245:Carbon Dioxide; D009569:Nitric Oxide