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Abstract #6665 Published in IGR 4-1
Effect of sympathetic denervation on rabbit choroidal blood flow
Chou PI; Lu DW; Chen JTOphthalmologica 2002; 216: 60-64
In this study, the authors demonstrate the existence of sympathetic innervation, and compare the effect of unilateral or bilateral superior cervical sympathectomy on albino rabbit choroidal blood flow (CBF) during changes in perfusion pressure (PP). Forty albino rabbits weighing between 2.0 and 3.0 kg were randomly divided into three groups. The bilateral sympathectomy group (group S) included ten rabbits (20 eyes) that received bilateral sympathectomy one week prior to the study. The unilateral sympathectomy group (group U) included 20 rabbits (20 eyes) that received unilateral sympathectomy one week prior to the study. Only the eyes ipsilateral to sympathectomy were utilized. The other ten rabbits (20 eyes) served as controls (group N), each received the same procedure as the experimental groups except that the superior cervical ganglion (SCG) was preserved. The blood cell flux (PF), velocity (V), and concentration of moving blood cells (CMBC) were recorded simultaneously by means of a laser Doppler flowmeter (Perimed PF4001), while the intraocular pressure was increased linearly with a syringe pump. When the PP decreased steadily, the PF, V, and CMBC remained constant until PP <55 mmHg, then decreased proportionally to the PP. When the PP decreased from 75 to 0 mmHg, the PF, V and CMBC decreased from 100 to 6.87 ± 0.97%, 8.44 ± 0.92%, and 18.67 ± 0.91% in group N, to 18.56 ± 1.62%, 19.30 ± 1.84%, and 38.02 ± 9.10% in group U, and to 18.38 ± 2.89%, 16.78 ± 1.48%, and 34.58 ± 4.42% in group S. The changes in PF, V, and CMBC were similar in groups S and U. Both group S and U had higher PF, V, and CMBC values than group N at comparable PPs below 55 mmHg. These results indicate that the SCG plays a role in CBF regulation. Both unilateral and bilateral sympathectomy led to a higher PF in both groups S and U rabbits, indicating increased CBF, while PP gradually decreased. This suggests that the rabbit choroid does not receive crossed innervation. The plateau response in each curve demonstrates the presence of autoregulation. This autoregulation was unchanged by either unilateral or bilateral sympathetic denervation.
Dr. P.I. Chou, Department of Ophthalmology, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan, Republic of China. pingichou@seed.net.tw
Classification:
5 Experimental glaucoma; animal models
6.11 Bloodflow measurements (Part of: 6 Clinical examination methods)
