Right Vagotomy Alters Heart Rate Variability Temporarily and Increases Total Choline Levels in Rats

Abstract

Objectives: The variability in the time intervals between heartbeats, known as heart rate variability (HRV), serves as a reflection of the intricate interplay between the sympathetic and parasympathetic neural systems. While the potential asymmetric effects of the left and right branches of the vagus nerve remain uncertain, this study aims to investigate the impact of unilateral, bilateral, and atropine interventions on HRV parameters and choline levels within cardiac tissue. Methods: 40 male adult Wistar albino rats were randomly assigned to the five groups (each n=8): sham-operated, atropine, right vagotomy, left vagotomy, and bilateral vagotomy. Heart rate variability (HRV) analyses were conducted, and the levels of total choline/acetylcholine in heart tissues were quantified. Statistical analyses were performed to assess the results. Results: The bilateral vagotomy and atropine groups exhibited higher heart rates and high frequency power (HF), along with reduced low frequency power (LF). Total power (TP) remained relatively unchanged. In the bilateral vagot- omy group, DFAα1 was significantly elevated while DFAα2 was reduced significantly. SD1 and SampEn were significantly lower in both the bilateral vagotomy and atropine groups. Notably, the right vagotomy group displayed significant changes primarily in the 15th minute, particularly in time- domain parameters, HF, TP, and SD1, with a significant in- crease observed in total choline levels. Conclusions: Our results revealed that asymmetrical vagal innervation induces distinct effects on heart rate variability parameters and total choline/acetylcholine levels in heart tissues. Our findings suggest that compensatory hemody- namic recovery, possibly driven by contralateral vagal overactivity, may contribute to these observed results.