Signal transduction variations

As indicated above, although less data is available that for herbicides, fungicides also have been implicated in the appearance of variations in phenolic metabolism. Molina et al. [116] have demostrated that the systemic acquired resistance signal transduction pathway, a salicylic acid-dependent plant-defence mechanism, mediates fungicide action in the plant. 

With modest increase in intracellular ROS levels, activation of NF-kB takes place, which protects the cell against oxidative stress [45], Direct root of ROS participation in signal transduction from cell membrane to intracellular metabolic reactions were recently described. Among them - activation of potential-dependent K-channels and variation of membrane potential, inhibition of cellular protein phosphatases and restriction of activity of MAP-kinase [49]. Such view on intracellular role of ROS consider them as second messengers, which together with cyclic nucleotides, calcium ions, and other biologically active compounds provides adequate cell response to the outer signals. 

It is commonly agreed that the signal transduction cascade, which is much less understood, is also of tremendous importance in mediating the effect of psychotropics. Components of this cascade include G proteins, ion channels, second messengers, and protein kinases (Manji et al. 1995). Interindividual and crossethnic variations in the genes coding these proteins likely exist and may also be responsible for the individual variability in drug response observed clinically. 

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