Excess dietary vitamin B-6 alters startle behavior of rats

Excessive intakes of vitamin B-6 can produce peripheral nervous system abnormalities, but few reports of central nervous system effects exist. We measured startle response, a central nervous system reflex, in rats fed excess pyridoxine to determine if subtle effects on central nervous system function could be detected. Female Long-Evans rats (218 g; n = 12) were fed either 1, 10, 100, 200 or 300 times the requirement of pyridoxine HCl (7 mg/kg) for 7 wk. Startle behavior was assessed weekly in chambers that allowed quantification of movement in response to stimuli. Food intake and body weights did not differ among groups (P 0.1), and urinary vitamin B-6 excretion reflected intake (P 0.001). Overt toxicity was not observed. There was a marginally significant effect of pyridoxine intake over time (P