Intraocular pressure effects of water loading and venous compression tests in normal and denervated pigmented rabbits.
We have compared IOP elevations induced by water-loading and by increased cephalic venous pressure in normal and denervated pigmented rabbits. Denervations were performed by sympathetic ganglionectomy and/or blockade of the sensory and autonomic innervation of the eye through retrobulbar anesthesia; retrobulbar anesthesia induced significant decreases of the basal IOP in control but not in ganglionectomized eyes. The water-loading test induced a peak pressure elevation approximately 30 min after water administration that could be counteracted by retrobulbar anesthesia. Ganglionectomized rabbits exhibited steeper IOP rises and greater IOP increases following water-loading than the control eyes; retrobulbar anesthesia in ganglionectomized eyes delayed the IOP response to water-loading. Compressions of the neck lasting 30 min elicited significant IOP elevations that were more pronounced in ganglionectomized eyes. In these eyes, retrobulbar anesthesia further increased the IOP rise elicited by neck compression. An IOP decrease below control values was observed at the end of the venous compression. The results indicate that an intact efferent innervation of the eye contributes to buffer IOP elevations induced by water-loading or cephalic venous stasis, presumably through the vascular effects of the ocular autonomic nerves.
Gual
A
A
Unitat de Fisiologia Humana, Facultat de Medicina de la Universitat de Barcelona, Spain.
Mintenig
G M
GM
Belmonte
C
C
D000818:Animals; D001340:Autonomic Nerve Block; D001794:Blood Pressure; D003250:Constriction; D005123:Eye / Q000294:innervation*; D015171:Ganglionectomy; D007429:Intraocular Pressure; D009333:Neck / Q000098:blood supply; D011817:Rabbits; D013562:Sympathectomy; D014867:Water
D014867:Water