Limits...
EPR spectroscopy of chlorpromazine-induced free radical formation in normal human melanocytes.

Otręba M, Zdybel M, Pilawa B, Beberok A, Wrześniok D, Rok J, Buszman E - Eur. Biophys. J. (2015)

Bottom Line: It was found that chlorpromazine at concentrations of 1 × 10(-7) and 1 × 10(-6) M contributed to the formation of free radicals (g values ~2) in a dose-dependent manner.The increase in free radical formation was accompanied by an increase in cytotoxicity, as shown by a tetrazolium assay.Homogeneous broadening of EPR lines, slow spin-lattice relaxation processes, and strong dipolar interactions characterized all the tested cellular samples.

View Article: PubMed Central - PubMed

Affiliation: Chair and Department of Pharmaceutical Chemistry, School of Pharmacy with the Division of Laboratory Medicine in Sosnowiec, Medical University of Silesia, Jagiellońska 4, 41-200, Sosnowiec, Poland.

ABSTRACT
The purpose of this study was to estimate the effect of chlorpromazine on free radical concentration in HEMn-DP melanocytes using electron paramagnetic resonance (EPR) spectroscopy. It was found that chlorpromazine at concentrations of 1 × 10(-7) and 1 × 10(-6) M contributed to the formation of free radicals (g values ~2) in a dose-dependent manner. The increase in free radical formation was accompanied by an increase in cytotoxicity, as shown by a tetrazolium assay. Homogeneous broadening of EPR lines, slow spin-lattice relaxation processes, and strong dipolar interactions characterized all the tested cellular samples. The performed examination of free radical formation in cells exposed to different chlorpromazine concentrations confirmed the usefulness of electron paramagnetic resonance spectroscopy to determine the effect of a drug on free radical production in a cellular model system in vitro.

No MeSH data available.


Related in: MedlinePlus

Influence of microwave power (M/M0) on linewidth (ΔBpp) of EPR spectra of HEMn-DP control cells (filled circle) and the cells treated with chlorpromazine in concentrations of 1 × 10−8 M (square), 1 × 10−7 M (triangle), and 1 × 10−6 M (diamond). M, M0 are the microwave power used during the measurement of the spectrum and the total microwave power produced by klystron (70 mW), respectively
© Copyright Policy - OpenAccess
Related In: Results  -  Collection


getmorefigures.php?uid=PMC4464733&req=5

Fig3: Influence of microwave power (M/M0) on linewidth (ΔBpp) of EPR spectra of HEMn-DP control cells (filled circle) and the cells treated with chlorpromazine in concentrations of 1 × 10−8 M (square), 1 × 10−7 M (triangle), and 1 × 10−6 M (diamond). M, M0 are the microwave power used during the measurement of the spectrum and the total microwave power produced by klystron (70 mW), respectively

Mentions: Influence of microwave power (M/Mo) on amplitude (A) and linewidth (ΔBpp) of EPR spectra of control cells and the cells treated with chlorpromazine at concentrations of 1 × 10−8, 1 × 10−7, and 1 × 10−6 M is presented in Figs. 2 and 3, respectively. The correlations between amplitudes, linewidths, and microwave powers are characteristic for homogeneously broadened EPR lines (Wertz and Bolton 1986; Eaton et al. 1998). The increase of linewidths (ΔBpp) with increasing microwave power presented in Fig. 3 indicates homogeneous broadening of EPR lines of the tested cells, because for inhomogeneously broadened EPR signals, linewidths do not change with microwave power. The obtained correlations (Figs. 2 and 3) are expected for free radicals homogeneously distributed in the cell samples. Amplitudes (A) of the EPR lines of HEMn-DP cells reached maximum at low values of microwave power (<70 mW) (Fig. 2), so slow spin–lattice relaxation processes existed in the tested samples. The slow, but relatively faster spin–lattice relaxation processes existed in control cells and cells treated with chlorpromazine at a concentration of 1 × 10−8 M (Fig. 2). Chlorpromazine treatment in concentrations of 1 × 10−7 and 1 × 10−6 M led to the rise of free radical content in melanocytes (Table 2) and to slower spin–lattice relaxation interactions (Fig. 2). Thus, it may be assumed that the presented increase in free radical concentrations in melanocytes after chlorpromazine treatment plays a critical role in drug toxicity directed to pigmented tissues, as a result of the generation of cellular oxidative stress.Fig. 2


EPR spectroscopy of chlorpromazine-induced free radical formation in normal human melanocytes.

Otręba M, Zdybel M, Pilawa B, Beberok A, Wrześniok D, Rok J, Buszman E - Eur. Biophys. J. (2015)

Influence of microwave power (M/M0) on linewidth (ΔBpp) of EPR spectra of HEMn-DP control cells (filled circle) and the cells treated with chlorpromazine in concentrations of 1 × 10−8 M (square), 1 × 10−7 M (triangle), and 1 × 10−6 M (diamond). M, M0 are the microwave power used during the measurement of the spectrum and the total microwave power produced by klystron (70 mW), respectively
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4464733&req=5

Fig3: Influence of microwave power (M/M0) on linewidth (ΔBpp) of EPR spectra of HEMn-DP control cells (filled circle) and the cells treated with chlorpromazine in concentrations of 1 × 10−8 M (square), 1 × 10−7 M (triangle), and 1 × 10−6 M (diamond). M, M0 are the microwave power used during the measurement of the spectrum and the total microwave power produced by klystron (70 mW), respectively
Mentions: Influence of microwave power (M/Mo) on amplitude (A) and linewidth (ΔBpp) of EPR spectra of control cells and the cells treated with chlorpromazine at concentrations of 1 × 10−8, 1 × 10−7, and 1 × 10−6 M is presented in Figs. 2 and 3, respectively. The correlations between amplitudes, linewidths, and microwave powers are characteristic for homogeneously broadened EPR lines (Wertz and Bolton 1986; Eaton et al. 1998). The increase of linewidths (ΔBpp) with increasing microwave power presented in Fig. 3 indicates homogeneous broadening of EPR lines of the tested cells, because for inhomogeneously broadened EPR signals, linewidths do not change with microwave power. The obtained correlations (Figs. 2 and 3) are expected for free radicals homogeneously distributed in the cell samples. Amplitudes (A) of the EPR lines of HEMn-DP cells reached maximum at low values of microwave power (<70 mW) (Fig. 2), so slow spin–lattice relaxation processes existed in the tested samples. The slow, but relatively faster spin–lattice relaxation processes existed in control cells and cells treated with chlorpromazine at a concentration of 1 × 10−8 M (Fig. 2). Chlorpromazine treatment in concentrations of 1 × 10−7 and 1 × 10−6 M led to the rise of free radical content in melanocytes (Table 2) and to slower spin–lattice relaxation interactions (Fig. 2). Thus, it may be assumed that the presented increase in free radical concentrations in melanocytes after chlorpromazine treatment plays a critical role in drug toxicity directed to pigmented tissues, as a result of the generation of cellular oxidative stress.Fig. 2

Bottom Line: It was found that chlorpromazine at concentrations of 1 × 10(-7) and 1 × 10(-6) M contributed to the formation of free radicals (g values ~2) in a dose-dependent manner.The increase in free radical formation was accompanied by an increase in cytotoxicity, as shown by a tetrazolium assay.Homogeneous broadening of EPR lines, slow spin-lattice relaxation processes, and strong dipolar interactions characterized all the tested cellular samples.

View Article: PubMed Central - PubMed

Affiliation: Chair and Department of Pharmaceutical Chemistry, School of Pharmacy with the Division of Laboratory Medicine in Sosnowiec, Medical University of Silesia, Jagiellońska 4, 41-200, Sosnowiec, Poland.

ABSTRACT
The purpose of this study was to estimate the effect of chlorpromazine on free radical concentration in HEMn-DP melanocytes using electron paramagnetic resonance (EPR) spectroscopy. It was found that chlorpromazine at concentrations of 1 × 10(-7) and 1 × 10(-6) M contributed to the formation of free radicals (g values ~2) in a dose-dependent manner. The increase in free radical formation was accompanied by an increase in cytotoxicity, as shown by a tetrazolium assay. Homogeneous broadening of EPR lines, slow spin-lattice relaxation processes, and strong dipolar interactions characterized all the tested cellular samples. The performed examination of free radical formation in cells exposed to different chlorpromazine concentrations confirmed the usefulness of electron paramagnetic resonance spectroscopy to determine the effect of a drug on free radical production in a cellular model system in vitro.

No MeSH data available.


Related in: MedlinePlus