Fast-scan cyclic voltammetry of 5-hydroxytryptamine

Abstract

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

Influence of different biological environments on the stability of serotonin detection on carbon-based electrodes

“…At this scan rate, no reversal peak was observed, suggestive of an irreversible oxidation mechanism occurring at both electrodes. However other researchers have shown that at higher scan rates (>100 V s -1 ), the cathodic peak (Epc) can be observed [11,15]. 5-HT undergoes an electrochemical-chemical mechanism.…”

“…Traditionally these recordings have been carried out on carbon fibre electrodes [9][10][11]; however boron-doped diamond [7,12] and carbon nanotube electrodes [13,14] have recently been shown to overcome electrode fouling from oxidative by-products. However limited insight is given on the influence of the 3 background matrix towards the stability and sensitivity of 5-HT measurements during these studies.…”

Ethanol Inhibits Clearance of Brain Serotonin by a Serotonin Transporter-Independent Mechanism

“…Because of adsorption of electrogenerated products at the electrode surface, electrode sensitivity for 5-HT can decline over the course of an experiment (Jackson et al, 1995). To monitor the sensitivity of the electrode to 5-HT, signal reproducibility was carefully monitored.…”

Detecting Subsecond Dopamine Release with Fast-Scan Cyclic Voltammetry in Vivo

“…The cyclic voltammogram for serotonin shows multiple oxidation and reduction peaks because its oxidation products are unstable and can break down into additional electroactive compounds. Cyclic voltammetry is particularly useful for serotonin detection compared with other electrochemical methods because the oxidation product, which can foul the electrode, is produced for only a few milliseconds and then is immediately reduced (45 ). In Fig.…”