Effects of Chloroform and Ammonia Solution on The Respiratory Function of White Mice: An Experimental Investigation of Reflex Mechanisms

Background: Respiration is regulated by the respiratory center of the medulla oblongata through both central and reflex mechanisms. Chemical agents with antagonistic actions on this system, such as chloroform (a central nervous system depressant) and ammonia (a peripheral reflex stimulant), provide a valuable experimental model for elucidating these regulatory pathways. Objective: To experimentally investigate and quantitatively evaluate the effects of chloroform vapor and ammonia solution on the respiratory function of white mice (Mus musculus), and to demonstrate the inhibitory and excitatory reflex mechanisms governing respiration. Materials and methods: Six healthy white mice (Mus musculus, BALB/c line; body weight 22–28 g; age 8–10 weeks) were used. After recording baseline respiratory rate over 1 min, each animal was placed in a hermetically sealed chamber and exposed for 30 s to a cotton pad soaked with 0.5 ml of chloroform. Subsequently, a cotton pad soaked with 0.3 ml of 25% ammonia solution was held 1.5–2 cm from the animal's nose for 5–10 s. Respiratory rate was measured at 10, 30, and 60 s following each exposure. Data were analyzed using Student's t-test, with statistical significance set at p < 0.05. Results: The mean baseline respiratory rate was 163.2 ± 4.8 breaths/min. Following chloroform exposure, the respiratory rate decreased by 42.3% compared with baseline at 30 s (94.1 ± 4.1 breaths/min; p < 0.05). Conversely, ammonia exposure produced a rapid reflex response with a latency of 1.8 ± 0.3 s, increasing the respiratory rate by 68.7% at 10 s (275.4 ± 8.6 breaths/min; p < 0.05). Conclusion: The findings experimentally confirm the existence of inhibitory and excitatory reflex mechanisms within the respiratory center of the medulla oblongata. The described methodology offers an effective tool for teaching respiratory physiology in higher medical education.

Respiratory organs, reflex mechanism, chloroform

Del Negro CA, Funk GD, Feldman JL. Breathing matters. Nature Reviews Neuroscience. 2018;19(6):351–367.

Sobirov UYu, Allayarov SR. Normal Physiology. Tashkent: Oʻzbekiston; 2021. 528 p. (In Uzbek).

Forman SA, Chin VA. General anesthetics and molecular mechanisms of unconsciousness. International Anesthesiology Clinics. 2019;46(3):43–53.

Damann N, Voets T, Nilius B. TRPs in our senses. Current Biology. 2020;18(18):R880–R889.

Karimov XYa, Inoyatov ASh. Medical Biology and General Genetics. Tashkent: Yangi Asr Avlodi; 2022. 416 p. (In Uzbek).

Franks NP. General anaesthesia: from molecular targets to neuronal pathways of sleep and arousal. Nature Reviews Neuroscience. 2018;9(5):370–386.

Bautista DM, Pellegrino M, Tsunozaki M. TRPA1: a gatekeeper for inflammation. Annual Review of Physiology. 2019;75:181–200.

Solt K, Forman SA. Correlating the clinical actions and molecular mechanisms of general anesthetics. Current Opinion in Anaesthesiology. 2020;20(4):300–306.

McCrory C, Blunnie WP, Moriarty DC. Elevation of intracranial pressure caused by smelling salts. Anaesthesia. 2018;53(11):1118–1120.