Cyclooxygenase-1 splice variant COX-3 (COX-3) (COX-3)

Cyclooxygenase-1 splice variant COX-3 (COX-3) is an alternative splice variant of the PTGS1 (COX-1) gene characterized by the retention of intron 1 (Chandrasekharan et al., 2002; NIH, 1.2.2). It was first identified in canine brain tissue and proposed as the primary central target for acetaminophen (paracetamol) and other antipyretic analgesics that lack significant peripheral anti-inflammatory activity (Simmons et al., 2002; NIH, 1.2.1). In dogs, COX-3 is a functional enzyme that catalyzes the synthesis of prostaglandins, particularly in the cerebral cortex (NIH, 1.2.2). However, its role in humans is controversial because the human intron 1 is 94 base pairs long, which causes a frame shift and results in a truncated protein that may lack cyclooxygenase activity (Wikipedia, 1.1.1; NIH, 1.2.5). Despite these species-specific differences, the "COX-3 hypothesis" remains a prominent pharmacological model for explaining the central analgesic and antipyretic effects of drugs like acetaminophen and metamizole (ResearchGate, 1.3.1). Research continues to investigate whether COX-3 or related variants contribute to central pain processing and thermoregulation in various disease states (The Scientist, 1.1.3).

Other names

COX-1bCOX-1vCOX-1 variant 1PTGS1 splice variantProstaglandin-endoperoxide synthase 1 splice variant

Inhibition of prostaglandin synthesis, particularly prostaglandin E2 (PGE2), within the central nervous system to mediate analgesic and antipyretic effects (ResearchGate, 1.3.1; NIH, 1.2.3).