Paper: Osteoclastic Activation In Periapical Lesions After NPY Knockout (IADR/AADR/CADR 87th General Session and Exhibition (April 1-4, 2009)): "After sympathectomy in rats there is an increase in osteoclast-mediated bone resorption as well as an increase in the number of osteoclasts on the sympathectomized side compared to the control. These findings suggest an inhibitory effect of the SNS on bone resorption via osteoclasts. Our objective was to determine if an SNS mediator, neuropeptide Y (NPY), affects osteoclastic activity after pulpal exposure."