A cost-effective UV spectrophotometric method for dopamine estimation in avian, piscine, and murine brain tissues

Abstract

This study aims to validate and adapt a streamlined UV spectrophotometric method for the quantification of dopamine in brain extracts across diverse biological models, specifically chicks, fish, and mice. The analytical approach utilizes the chemical reaction between dopamine, potassium ferricyanide, and Iron (III) to produce a stable, soluble Prussian blue complex. This complex displays maximum absorbance at a wavelength of 735 nm. A calibration curve for dopamine hydrochloride was established, demonstrating strong linearity within a concentration range of 0.1–10 µg/ml. This protocol adapts the foundational work of Guo et al. (2009), transitioning the application from pharmaceutical and agricultural samples to complex biological brain tissues. Quantitative analysis revealed significant variations in dopamine concentrations across the subjects. The highest dopamine concentration was detected in mouse brain tissue, corresponding to 479.3 µg/g free dopamine (593.2 µg/g dopamine hydrochloride), followed by fish brain tissue with 325.9 µg/g free dopamine (403.4 µg/g dopamine hydrochloride), while the lowest concentration was observed in chicken brain tissue, corresponding to 77.4 µg/g free dopamine (95.8 µg/g dopamine hydrochloride). The proposed UV spectrophotometric technique provides a highly accessible, cost-effective alternative to sophisticated and expensive methods like HPLC, chemiluminescence, or ELISA. Given its simplicity and accuracy, this method is highly suitable for neuropharmacological research and routine laboratory estimations of dopamine in varied animal models.