title: [Effects of stimulating some dorsohypothalamic nuclei on the firing activity of bulbar respiratory neurons during hypoxia].
abstract: To specify the respiration regulating function of the dorsal hypothalamus, response of the firing activity of neurons in the bulbar respiration center (BRC) and external respiration to stimulation of some dorsohypothalamic nuclei in rats with different levels of the functional activity was studied. Functional hyper- or hypoactivity was modeled in a laboratory pressure chamber. In the normal functional condition, i.e. at the standard atmospheric pressure (normoxia) and in low-oxygen atmosphere stimulation of the nuclei mainly led to activation of both external respiration and background electrical activity of BRC neurons. Slight reduction of inspired oxygen to simulate "ascent" to 4000-5000 m increased the neuronal activity in terms of the firing rate. In the situation, the moderating effect of hypothalamic nuclei stimulation was less evident than in normoxia, although it overrode its inhibitory action. As atmospheric oxygen continued going down to levels imitating the altitude of 7500-8000 m, the rats' functional activity was getting low which could not but affect neuronal firing. The firing rate decreased noticeably; yet, the facilitatory effect of hypothalamic nuclei stimulation was still present. After the return of animals to the normal atmospheric pressure, both the spontaneous rhythm of neuronal firing and reaction to stimulation gradually recovered their initial patterns.
authors.forename: M A
authors.initials: MA
authors.lastname: Karapetian
authors.forename: N Iu
authors.initials: NIu
authors.lastname: Adamian
mesh_terms: D000200:Action Potentials / Q000187:drug effects* / Q000502:physiology; D000531:Altitude; D000818:Animals; D001273:Atmosphere Exposure Chambers; D001933:Brain Stem / Q000187:drug effects* / Q000502:physiology; D007031:Hypothalamus / Q000187:drug effects* / Q000502:physiology; D000860:Hypoxia / Q000503:physiopathology; D008297:Male; D008839:Microelectrodes; D009474:Neurons / Q000187:drug effects* / Q000502:physiology; D010100:Oxygen / Q000494:pharmacology* / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar; D012119:Respiration / Q000187:drug effects
chemical_list: D010100:Oxygen