{'fraction_non_alphanumeric': 0.042846768336964415, 'fraction_numerical': 0.026143790849673203, 'mean_word_length': 4.624489795918367, 'pattern_counts': {'":': 0, '<': 1, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Cerebral artery resistance is directly related to sympathetic nerve activity in men

Cerebral arterial resistance may play a role in determining the level of sympathetic nerve activity (SNA) at rest. We hypothesised that resistance to blood flow in the internal carotid, vertebral and the basilar arteries (ICA, VA, BA) is directly related to the level of muscle SNA (MSNA). In 4 men aged 20–52 years, blood flow in the ICA, VA and BA was measured using MR phase contrast imaging at 2 locations (1 cm below the VA convergence and 1 cm above) with simultaneous brachial blood pressure measurements (automated cuff). MSNA was measured via peroneal microneurography. Resistance in each vessel was calculated as mean arterial pressure/blood flow. Resting MSNA (30–82 bursts/100 heart beats) was positively related to vascular resistance in the left and right ICA (r = 0.87, r = 0.75, P<0.05), right and left VA (r = 0.87, r = 0.85, P=0.05). There was a weak positive relationship between MSNA and vascular resistance in the BA (r = 0.40). In summary, men with high resistance to blood flow through the ICA and VA have high MSNA. Thus, cerebral arterial resistance might determine the set point of sympathetic activity. This is important since high levels of SNA observed in hypertensive patients may be due to elevated cerebral vascular resistance. British Heart Foundation funded.