Fast-scan cyclic voltammetry of 5-hydroxytryptamine.
Fast-scan cyclic voltammetry, a demonstrated analytical method for the in vivo detection of dopamine, is extended to the detection of in vitro and in vivo 5-hydroxytryptamine (5-HT) with the use of a specific potential wave form applied at 1000 V/s. The wave form, 0.2 to 1.0 to -0.1 to 0.2 V, is employed to accelerate electrode response times which are significantly slower with other wave forms due to the adsorption of 5-HT. The scan rate of 1000 V/s enables follow-up reactions which lead to the formation of strongly adsorptive products to be outrun. The peak current at a carbon fiber disk microelectrode exposed to 1 microM 5-HT in flow injection experiments is 1 nA, with a half-rise time of less than 200 ms. The peak current of Nafion-coated electrodes exposed to the same concentration of 5-HT is 5 nA, with a half-rise time on the order of 400 ms. The rate of adsorption of 5-HT was determined to be 4.22 +/- 0.33 s-1. Several compounds present in brain tissue as well as the pharmacological agents used to elicit 5-HT release in the caudate of the rat were evaluated. Those which gave a response could be differentiated from 5-HT on the basis of respective oxidative and reductive peak potentials. Nafion-coated electrodes were used to monitor transient increases in both dopamine and exogenous 5-HT in the caudate of the anesthetized rat in response to electrical stimulation. The rate of cellular uptake of 5-HT was shown to be 3-fold slower than dopamine uptake. NS-15841
Jackson
B P
BP
Department of Chemistry, University of North Carolina at Chapel Hill 27599-3290.
Dietz
S M
SM
Wightman
R M
RM
D000818:Animals; D001923:Brain Chemistry; D002244:Carbon; D000077482:Carbon Fiber; D004553:Electric Conductivity; D005465:Fluorocarbon Polymers; D008297:Male; D008839:Microelectrodes; D051381:Rats; D017207:Rats, Sprague-Dawley; D012680:Sensitivity and Specificity; D012701:Serotonin / Q000032:analysis*
D000077482:Carbon Fiber; D005465:Fluorocarbon Polymers; D012701:Serotonin; C040402:perfluorosulfonic acid; D002244:Carbon