title: In vivo direct monitoring of interstitial norepinephrine levels at the sinoatrial node.
abstract: We assessed in vivo interstitial norepinephrine (NE) levels at the sinoatrial node in rabbits, using microdialysis technique. A dialysis probe was implanted adjacent to the sinoatrial node of an anesthetized rabbit and dialysate was sampled during sympathetic nerve stimulation. Atrial dialysate NE concentration correlated well with heart rate. Desipramine significantly increased dialysate NE concentrations both before and during sympathetic nerve stimulation compared with the absence of desipramine. However, desipramine did not affect the relation between heart rate and dialysate NE concentration. These results suggest that atrial dialysate NE level reflects the relative change of NE concentration in the synaptic cleft. Microdialysis is a powerful tool to assess in vivo interstitial NE levels at the sinoatrial node.
authors.affiliation: Department of Cardiovascular Dynamics, Advanced Medical Engineering Center, National Cardiovascular Center Research Institute, Osaka, Japan. shujismz@ri.ncvc.go.jp <shujismz@ri.ncvc.go.jp>
authors.forename: Shuji
authors.initials: S
authors.lastname: Shimizu
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Akiyama
authors.forename: Toru
authors.initials: T
authors.lastname: Kawada
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Shishido
authors.forename: Masaki
authors.initials: M
authors.lastname: Mizuno
authors.forename: Atsunori
authors.initials: A
authors.lastname: Kamiya
authors.forename: Toji
authors.initials: T
authors.lastname: Yamazaki
authors.forename: Shunji
authors.initials: S
authors.lastname: Sano
authors.forename: Masaru
authors.initials: M
authors.lastname: Sugimachi
mesh_terms: D000818:Animals; D004558:Electric Stimulation; D045604:Extracellular Fluid / Q000737:chemistry*; D006339:Heart Rate; D017551:Microdialysis; D009638:Norepinephrine / Q000032:analysis*; D011817:Rabbits; D012849:Sinoatrial Node / Q000737:chemistry*; D013564:Sympathetic Nervous System / Q000502:physiology
chemical_list: D009638:Norepinephrine