Table 3.

Effects of carbamate pesticides on tau protein

Type of study	Sample	Type of pesticide	Exposure data	Tau phosphorylation	GSK-3β	PP2A	Other mechanisms	Ref.
Experimental studies	C57BL/6 and 129/Sv mice	Maneb	Concentration: 30 mg/kg. Exposure time for 6 wk	Decreased	Decreased	NA	No changes in tau phosphorylation. However, if combined with paraquat, tau phosphorylation was enhanced in Ser202 (38% more), Ser262 (28% more) and Ser396/404 (141% more)	[31]
Experimental studies	Sprague-Dawly rats	Carbofuran	Concentration: 1 mg/kg. Exposure time of 28 d	Increased	Increased	Decreased	Increased phosphorylation of tau was observed in Ser198/199/202, Thr205 and Ser404. In addition, there was an increase in GSK-3β and a decrease in PP2A	[32]
Experimental studies	NMRI mouse	Carbaryl	Concentrations: 0.5, 5.0, 20.0 mg/kg. Single dose	Increased	NA	NA	In the hippocampus, levels of phosphorylated tau increased by 135% in rats exposed to low, medium and high doses. In cerebral cortex, there was oscillating increase of 155% to 210% in tau phosphorylation	[54]
Experimental studies	Sprague-Dawly rats	Deltametrin (P)/carbofuran (Cs)	Concentration: NA. Exposure time for 28 d	Increased	Increased	Decreased	Exposure induced tau hyperphosphorylation and GSK-3β activation, as well as PP2A phosphatase inhibition	[63]
Review studies	Multiple studies	Cs	NA	Increased	Increased	NA	Exposure induced increased activity of kinase, thereby increasing phosphorylation of tau protein	[62]
Review studies	Multiple studies	Pyridine carbamate	Concentrations: 15.7 μM. Single dose	Decreased	NA	NA	An inhibitory effect on phosphorylation was observed. This prevented the aggregation of tau protein	[64]

Ser: Serine; Thr: Treonine; GSK-3β: Glycogen synthase kinase 3 beta; PP2A: Protein phosphatase-2A; NA: Not available; Cs: Carbamate; Ps: Pyrethroids.