Comparative Analysis of the Central Nervous System Safety Pharmacology Profiles of Caffeine and Taurine in Male and Female Mice Using a Modified Irwin Test

Caffeine is a psychoactive methylxanthine that stimulates the central nervous system (CNS) mainly through adenosine receptor antagonism, whereas taurine is a sulfur-containing -amino acid involved in neurotransmitter modulation and cellular homeostasis.Although both compounds are widely used in energy drink formulations, direct comparison of their CNS safety pharmacology profiles under standardized conditions remains limited.The present study evaluated acute neurobehavioral responses to caffeine and taurine in male and female Institute for Cancer Research mice using a modified Irwin test combined with body temperature monitoring.Mice were orally administered saline, caffeine (20 mg/kg), or taurine (400 mg/kg).CNS safety pharmacology endpoints were assessed before administration and at 0.5, 1, 2, 6, and 24 h after dosing.Caffeine induced marked but transient locomotor stimulation between 0.5 and 2 h postadministration, accompanied by mild traction impairment and intermittent piloerection, followed by gradual recovery.Taurine produced milder and less frequent behavioral changes, including reduced traction performance, sporadic piloerection, and temporary decreases in abdominal tone.Response patterns were generally comparable between male and female mice, although several early neurobehavioral effects were numerically more frequent in females.Body temperature remained largely stable, and severe neurotoxic signs, including convulsion, respiratory distress, and mortality, were not observed.These findings indicate that caffeine exerted stronger transient stimulatory and neurobehavioral effects on the CNS than taurine under the same experimental framework.