Wireless fast-scan cyclic voltammetry measurement of histamine using WINCS--a proof-of-principle study.

Histamine is among the most poorly understood biogenic amines, yet the histaminergic system spreads throughout the brain and has been implicated in functions as diverse as homeostasis and synaptic plasticity. Not surprisingly then, it has been linked to a number of conditions including minimally conscious state, persistent vegetative state, epilepsy, addiction, cluster headache, essential tremor, and Parkinson's disease. We have previously reported that the Wireless Instantaneous Neurotransmitter Concentration Sensing (WINCS) system can monitor dopamine, serotonin, and adenosine using fast-scan cyclic voltammetry (FSCV). Here, we demonstrate the expanded capability of the WINCS system to measure histamine. The optimal FSCV waveform was determined to be a triangle wave scanned between -0.4 and +1.4 V at a rate of 400 V s(-1) applied at 10 Hz. Using this optimized FSCV parameter, we found histamine release was induced by high frequency electrical stimulation at the tuberomammillary nucleus in rat brain slices. Our results suggest that the WINCS system can provide reliable, high fidelity measurements of histamine, consistently showing oxidative currents at +1.3 V, a finding that may have important clinical implications.