Hypoglycaemia-induced changes in the patterns of breathing in rodents

Mobley, Alastair (2015). Hypoglycaemia-induced changes in the patterns of breathing in rodents. University of Birmingham. M.Res.

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Abstract

Hypoglycaemia induces hyperpnoea and changes in breathing pattern either directly or via a metabolic intermediate. We hypothesised hypoglycaemia would augment response to hypercapnia and hypoxia equally in mice and rats but induce active expiration in hypercapnia only. Using whole-body plethysmography, the response to hypercapnia (8% C0 $_2$ , hypoxia (10% 0 $_2$ ) and hyperoxia (100% 0 $_2$ ) were recorded under normoglycaemic, fasted and insulin-induced hypoglycaemic conditions in male Wistar rats and C57BL/6 mice.

Hypoglycaemia increased baseline ventilation and C0 $_2$ sensitivity but not 0 $_2$ sensitivity in conscious rats but had no effect in mice. Responses in anaesthetised rats were blunted and baseline frequency was reduced from 100BPM±20 to 70BPM±20. In conscious rats, the Ti:Te ratio was increased from 0.6±0.05 to 0.9±0.1 in hypercapnia indicating a active expiration that was not observed in response to hypoxia with only a increase from 0.6±0.05 to 0.7±0.1 at the same tidal volume.

In conclusion hypoglycaemia induced changes in respiration are observed in rats but not in mice. This may be attributed to differences in counter-regulatory response between species. Hypercapnia and hypoxia do not induce the same changes in ventilatory patterns.

Type of Work:

Thesis (Masters by Research > M.Res.)

Award Type:

Masters by Research > M.Res.

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