Vitamin A is an essential micronutrient involved in growth, immune regulation, and central nervous system function; however, excessive intake may disrupt systemic homeostasis. This study investigated the electrophysiological effects of experimental hypervitaminosis A on hippocampal activity and cardiac function in male Wistar rats. Animals received a supraphysiological dose of vitamin A (50,000 IU/kg, intraperitoneally) once daily for 3, 7, or 14 days. Serum calcium levels were quantified, and electrophysiological recordings were obtained from the CA1 hippocampal region (EEG) and through electrocardiography (ECG). Vitamin A administration produced a time-dependent increase in total hippocampal spectral power. Power elevations were observed across multiple frequency bands, particularly theta (4–8 Hz), α (8–12 Hz), β (12–28 Hz), and γ (28–40 Hz) oscillations after 7 and 14 days of exposure. Serum calcium levels showed modest increases but remained within physiological reference ranges. Cardiac assessment revealed increased heart rate accompanied by reductions in R–R and QT intervals while maintaining sinus rhythm and preserved ECG morphology. These findings demonstrate that short-term exposure to supraphysiological vitamin A levels alters hippocampal oscillatory dynamics and modulates cardiac electrophysiological parameters in rats. Although the functional and mechanistic implications require further investigation, the results indicate that excessive vitamin A intake can influence neurocardiac electrophysiological homeostasis even in the absence of overt hypercalcemia.
Hartcopff et al. (Wed,) studied this question.
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