ABSTRACT
Objective The study is to evaluate autonomic nervous activity and its circadian rhythm over a 24 hour period in children with beta adrenergic receptor (? AR) hypersensitivity and hyperthyroidism by analysis of heart rate variability (HRV), and to discuss the diagnosis value of autonomic nervous tone change in children with ? AR hypersensitivity Methods Indexes of HRV are measured in 23 children with ? AR hypersensitivity, and 13 hyperthyroidism and 26 healthy control Time domain indexes and spectral indexes of HRV are derived and the night day difference of HRV is analyzed Results 1 Spectral indexes over a 24 hour period: In patients with ? AR hypersensitivity and hyperthyroidism, there are significant increases both in low frequency (LF) to high frequency (HF) ratio (LF/HF) and HF normalized units (HF UN ) compared with the control group Whereas there are no significant changes compared with ? AR hypersensitivity and hyperthyroidism 2 Spectral indexes during waking hours: In patients with? AR hypersensitivity and hyperthyroidism, there are no significant difference in LF normalized units (LF UN ), HF UN and LF/HF; whereas there are significance changes compared with normal subject 3 Spectral indexes during sleeping hours: there are no significantly differences in indexes of HF, LF UN and HF UN compared with ? AR hypersensitivity and normal subject, whereas these indexes significance changes compared with hyperthyroidism 4 Time domain indexes change over a 24 hour period: There are significant changes of the night day difference in time domain indexes with? AR hypersensitivity or control group, in which rMSSD and pNN50 are most sensitive indexes Whereas there are significant difference in patients with hyperthyroidism in any time domain indexes of HRV compared with control group or ? AR hypersensitivity, and the night day difference in HRV is significantly smaller compared with ? AR hypersensitivity or control group, the circadian rhythm is almost disappeared Conclusion It is showed that the children with? AR hypersensitivity have no difference from normal subjects in autonomic nervous system activity, but these patients respond differently to the catecholamine stimulus, which results in changes in autonomic balance, and relatively increase of sympathetic nervous activity But cardiac autonomic nervous activity still has a circadian rhythm, which is similar to normal subject The analysis of HRV may play an important role in diagnosis? AR hypersensitivity
ABSTRACT
With 58 of New Zeeland rabbits, following experiments were carried out: (1) the dose-response relationship of MSG which decreased the body temperat ure; (2) the effects of the propranolol and the anisodamine (654-2) on the action of decreasing body temperature by MSG. The results indicated: following intravenous administration of MSG at a dose of 0.5g/kg. w and 1.0g/kg. w, the body temperature of rabbits were decreased significantly, but at a dose of 0.1g/kg.w, the change of temperature was insignificant.Pretreatment with propranolol did not affect the effect of MSG decreasing body temperature which was blocked significantly by anisodamine, one of blocker of the cholinergic nerve. The authors suggest that the effect of MSG decreasing body temperature may depend on the cholinergic nerve.