Montelukast in Parkinson Disease

Parkinson's disease (PD) is the second most common neurodegenerative disorder after Alzheimer's disease (AD). Clinical manifestations of PD can vary, but a formal diagnosis relies on the presence of bradykinesia with rigidity and/or rest tremor according to Movement Disorder Society (MDS) criteria for PD. Non-motor symptoms, such as hyposmia, constipation, depression, and rapid eye movement (REM) sleep behavior disorder, are common and can in many cases manifest before classical motor symptoms. In later years, more emphasis has been put on non-motor symptoms, especially in the early stages of PD and which is evident in the proposed prodromal PD criterion by MDS.

Leukotrienes are along with prostaglandins, lipoxins, and thromboxanes included in a group of long-chain fatty acids known as eicosanoids. They are known to play important parts in the inflammatory response such as leukocyte chemotaxis, vascular leakage, and astrocyte proliferation, and were first described by Bengt Samuelsson and colleagues in 1983. Leukotrienes (LT) are synthesized from free arachidonic acid (AA) by the enzyme 5-lipoxygenase (5-LOX) into LTA4, which is then further metabolized into LTB4, C4, D4, and E4. LTC4, D4, and E4 are grouped by their molecule structure to form the cysteinyl leukotrienes and they mainly activate two receptors, CysLT1 and CysLT2. CysLT1 is a Gq/11 family G-protein-coupled receptor with signaling through phospholipase C and Ca2+ mobilization