Neuropeptide Y levels in the aqueous humor of rabbits

The concentration of neuropeptide Y in the aqueous humor (NPYaq) did not change during the circadian cycle in rabbits. However, NPYaq also did not decrease after superior cervical ganglionectomy or preganglionic section of the cervical sympathetic trunk (decentralization). Nor did NPYaq change after either stimulation, with para-aminoclonidine, or blockade, with rauwolscine, of prejunctional ocular alpha2-adrenergic receptors. Therefore, NPYaq does not reflect NPY release from ocular sympathetic nerves in rabbits.