However, sympathetic blockade at the level of the neck eliminated the beta-1 blockade induced attenuation in delta MCA V(mean) (10.2 2.5 cm s(-1)). These results indicate that a reduced ability to increase CO during exercise limits blood flow to a vital organ like the brain and that this flow limitation is likely to be by way of the sympathetic nervous system.
PMID: 10971220 [PubMed - indexed for MEDLINE]
1. Acta Physiol Scand. 2000 Sep;170(1):33-8.