Conclusion
Our results showed that TRPV1 played a role in the modulation of neuroinflammation of PDD, and could potentially be a new target for treatment.
Methods
We used 6-hydroxydopamine (6-OHDA) to induce PDD in mice. We then used the Morris water maze and Bio-Plex to test learning and inflammatory mediators in mouse plasma. Western blotting and immunostaining were used to examine TRPV1 pathway in the hippocampus and medial prefrontal cortex (mPFC).
Results
On acquisition days 3 (Control = 4.40 ± 0.8 sec, PDD = 9.82 ± 1.52 sec, EA = 5.04 ± 0.58 sec, Riva = 4.75 ± 0.87 sec; P=0.001) and 4, reversal learning days 1, 2, 3 (Control = 2.86 ± 0.46 sec, PDD = 9.80 ± 1.83 sec, EA = 4.6 ± 0.82 sec, Riva = 4.6 ± 1.03 sec; P=0.001) and 4, PDD mice showed significantly longer escape latency than the other three groups. Results showed that several cytokines were up-regulated in PDD mice and reversed by EA and rivastigmine. TRPV1 and downstream molecules were up-regulated in PDD mice and further reversed by EA and rivastigmine. Interestingly, α7 nicotinic receptors and parvalbumin levels in both the hippocampus and prefrontal cortex increased in EA-treated mice, but not in rivastigmine-treated mice.