Abstract P204: Gender-specific Relationships Between Plasma Levels of Endocannabinoids and Vagal and Sympathetic Control of Heart Rate in Normotensive Obese Older Adults

• Published in: Hypertension (Dallas, Tex. 1979) Vol. 70; no. suppl_1
• Main Authors: Schaich, Chris L, Shaltout, Hossam A, Kovach, Alex, Grabenauer, Megan, Thomas, Brian F, Brinkley, Tina E, Nicklas, Barbara J, Diz, Debra I
• Format: Journal Article
• Language: English
• Published: 01.09.2017
• ISSN: 0194-911X; 1524-4563
• DOI: 10.1161/hyp.70.suppl_1.p204

Abstract only Previous studies in obese individuals indicate higher circulating endocannabinoids anandamide (AEA) and 2-arachidonoylglycerol (2-AG) than in lean counterparts. However, the association between plasma endocannabinoids and autonomic control of blood pressure and heart rate has not been assessed in obesity. In a sample of normotensive, obese older adults we analyzed plasma content of the endocannabinoids AEA and total AG using mass spectrometry and examined correlations with various indices of spontaneous sympathovagal activity. Spontaneous baroreflex sensitivity (BRS) for heart rate control was calculated by spectral analysis of arterial pressure (AP) time (Sequence [Seq] Up, Seq Down and Seq All) and frequency (low-frequency [LF] and high-frequency [HF] α) domains from continuous resting AP recordings. In addition, time domain analysis was used to calculate heart rate variability (HRV) and blood pressure variability, indices of cardiac vagal tone and vascular sympathetic tone, respectively. The sample included 8 males and 17 females with a mean age of 68.4 ± 0.6 years, a mean body mass index of 35.0 ± 0.8 kg/m 2 , and mean AP of 101.0 ± 2.2 mmHg. Across the complete sample, we report a significant inverse correlation between plasma AG content and HFα, an index of the vagally-mediated parasympathetic spontaneous BRS ( r = -0.50, P < 0.05). We further report a significant inverse correlation between plasma AG and the vagal spontaneous BRS (Seq Up) in males ( r = -0.87, P < 0.01) but not in females. However, in females but not males we found significant positive relationships between AEA and LFα, an index of sympathetic spontaneous BRS ( r = 0.49, P < 0.05), and AEA and HRV ( r = 0.50, P < 0.05). These results are consistent with a role for the endocannabinoid system to modulate autonomic control of the circulation in populations at risk for hypertension and cardiovascular disease, and suggest gender differences that have yet to be elucidated.