What question did this study set out to answer?

Investigate the direct electrophysiological actions of the local anesthetic tetracaine on ionic currents in isolated mammalian heart cells.

July 1, 1986The Journal of PhysiologyOpen Access

Electrophysiological effects of tetracaine in single guinea‐pig ventricular myocytes.

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Population

Enzymatically dissociated single guinea-pig ventricular cells

Design

Preclinical

Authors

ECEdward CarmelietElectrophysiology MMMartin MoradElectrophysiology GHG. HeydenGöteborgs Stads

Discussion

Member takes

Implication

Tetracaine's ion channel effects in guinea-pig myocytes should not alter clinical use; leaves open translational relevance to human electrophysiology.

Key Points

Investigate the direct electrophysiological actions of the local anesthetic tetracaine on ionic currents in isolated mammalian heart cells.
Enzymatically dissociated single guinea-pig ventricular myocytes were examined using a two-microelectrode voltage-clamp technique at room temperature.
Myocytes were pre-incubated with cesium (Cs+) to minimize contaminating delayed outward potassium currents, with further testing using strontium (Sr2+) and barium (Ba2+) as charge carriers.
Tetracaine reduced the maximum rate of rise of the action potential voltage-dependently, with a KD of 0.77 µM at -80 mV versus 6.2 µM at -95 mV.
Application of 20 µM tetracaine reduced the inwardly rectifying K+ current by approximately 50%, while roughly 200 µM was required to suppress the delayed K+ current.
Tetracaine reduced Ca2+ current amplitude and accelerated decay primarily by suppressing the slowly inactivating component (apparent KD = 80 µM, Hill coefficient nH = 2) without substantially altering its inactivation time constant.

Structured PICO

Population

Enzymatically dissociated single guinea-pig ventricular cells

Intervention

Tetracaine (various concentrations, e.g., 20 microM)

Outcome

Effect on ionic currents (action potential rate of rise, K+ currents, Ca2+ currents)surrogate

Tetracaine directly inhibits high threshold Ca2+ channels and K+ currents in guinea-pig ventricular myocytes.

Cite This Study

Carmeliet et al. (1986) studied this question.

synapsesocial.com/papers/6a9583cb9f3a8012a37d09de https://doi.org/10.1113/jphysiol.1986.sp016146

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Implication

Tetracaine's ion channel effects in guinea-pig myocytes should not alter clinical use; leaves open translational relevance to human electrophysiology.

Electrophysiological effects of tetracaine in single guinea‐pig ventricular myocytes.

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

Electrophysiological effects of tetracaine in single guinea‐pig ventricular myocytes.

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

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Also Consider