ABSTRACT
@#INTRODUCTION: Subclinical changes that occur in the heart at an early age may provide valuable information to outline prevention strategies for cardiovascular diseases. Heart rate variability (HRV) reflects regulation of autonomic balance, heart, and vascular tone, which are the determinants of blood pressure. Therefore, this study aimed to determine the difference in heart rate variability (HRV) of Malay male young adult with their BMI and adiposity level. MATERIALS AND METHODS: A total of 201 Malay male young adult aged between 19 to 24 years old were screened and their BMI and adiposity level were measured. Three non -invasive tests; Valsalva Manoeuvre, orthostatic response and 30/15 ratio of heart rate were performed. Short term HRV time and frequency domains were recorded. RESULTS: Despite few significant differences in HRV parameters of overweight/obese subjects, the result is inconclusive to conclude any reduced variability. However, those with high adiposity regardless of their BMI reported significantly lower mean of R -R SD in time domain and lower mean of LF/HF ratio in frequency domain. The orthostatic reflex results revealed that high adiposity subjects had significantly lower mean of LF and HF. A decrement of -0.28 ms2 HF/LF during Valsalva manoeuvre, -0.35 LF ms2 in orthostatic reflex and 0.33 ms2 in orthostatic reflex per 1% of body fat percentage were observed. CONCLUSION: HRV parameters were inversely proportional to the adiposity level which was suggestive of modulation of sympathetic function can occur at an early age.
ABSTRACT
The recent development of tools to decipher the intricacies of neural networks has improved our understanding of brain function. Optogenetics allows one to assess the direct outcome of activating a genetically-distinct population of neurons. Neurons are tagged with light-sensitive channels followed by photo-activation with an appropriate wavelength of light to functionally activate or silence them, resulting in quantifiable changes in the periphery. Capturing and manipulating activated neuron ensembles, is a recently-designed technique to permanently label activated neurons responsible for a physiological function and manipulate them. On the other hand, neurons can be transfected with genetically-encoded Ca indicators to capture the interplay between them that modulates autonomic end-points or somatic behavior. These techniques work with millisecond temporal precision. In addition, neurons can be manipulated chronically to simulate physiological aberrations by transfecting designer G-protein-coupled receptors exclusively activated by designer drugs. In this review, we elaborate on the fundamental concepts and applications of these techniques in research.