title: Calibration of neurotransmitter release from neural cells for therapeutic implants.
abstract: In this work we quantified the in vitro calibration relationships between high frequency electrical stimulation and GABA and glutamate release in both mature retinoic acid differentiated P19 neurons and immortalized embryonic cortical cells engineered to express glutamic acid decarboxylase, GAD65. Extracellular glutamate and GABA was quantified by 2D gas chromatography and time of flight mass spectrometry after stimulation at varying amplitudes and frequencies. Amplitude sweeps resulted in a linear calibration for P19 neurons; the level of neurotransmitter varied over one order of magnitude from ~ 200 pg/neuron to ~ 1.2 ng/neuron for glutamate and ~ 1 ng/neuron to ~ 2 ng/neuron for GABA, depending on the stimulation amplitude. Frequency sweeps resulted in a peak release at 250 Hz for glutamate and 400 Hz for GABA in P19 cells. The GABA transporter inhibitor, nipecotic acid, increased extracellular GABA levels and decrease glutamate. In contrast the embryonic cortical cells had a strongly nonlinear dependency of release on stimulation amplitude, and a weak dependence on frequency. These cells had roughly equal extracellular glutamate and GABA levels after stimulation despite the expression of GAD65. In addition glutamate and GABA levels were insensitive to nipecotic acid. These results demonstrate an ability to calibrate and tune neurotransmitter release from neural cells using high frequency stimulation parameters.
authors: Department of Agricultural and Biological Engineering, USA.
authors: Sabrina S
authors: SS
authors: Jedlicka
authors: Maria
authors: M
authors: Dadarlat
authors: Travis
authors: T
authors: Hassell
authors: Yanzhu
authors: Y
authors: Lin
authors: Aaron
authors: A
authors: Young
authors: Min
authors: M
authors: Zhang
authors: Pedro
authors: P
authors: Irazoqui
authors: Jenna L
authors: JL
authors: Rickus
mesh_terms: D000200:Action Potentials / Q000187:drug effects / Q000502:physiology; D000818:Animals; D016380:Brain Tissue Transplantation / Q000379:methods*; D018929:Cell Culture Techniques / Q000379:methods; D002460:Cell Line; D002461:Cell Line, Transformed; D046690:Deep Brain Stimulation / Q000009:adverse effects / Q000379:methods*; D004567:Electrodes, Implanted; D045604:Extracellular Fluid / Q000378:metabolism; D005968:Glutamate Decarboxylase / Q000378:metabolism; D018698:Glutamic Acid / Q000378:metabolism; D051379:Mice; D009474:Neurons / Q000187:drug effects / Q000378:metabolism*; D018377:Neurotransmitter Agents / Q000378:metabolism*; D009557:Nipecotic Acids / Q000494:pharmacology; D019736:Prostheses and Implants; D017655:Silicon Compounds / Q000627:therapeutic use*; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology; D005680:gamma-Aminobutyric Acid / Q000378:metabolism
chemical_list: D018377:Neurotransmitter Agents; D009557:Nipecotic Acids; D017655:Silicon Compounds; C030278:nipecotic acid; D018698:Glutamic Acid; D005680:gamma-Aminobutyric Acid; D005968:Glutamate Decarboxylase; C401141:glutamate decarboxylase 2