TY - JOUR
T1 - Quantitative anatomy of the guinea pig endolymphatic sac
AU - Pettit, Kelli
AU - Henson, Miriam M.
AU - Henson, O. W.
AU - Gewalt, Sally L.
AU - Salt, Alec N.
N1 - Funding Information:
This study was supported by Research Grants T32 DC00022 (K.P.), RO1 DC01368 (A.N.S.), RO1 DC00114 (O.W.H.). Histologic processing of specimens prepared in our laboratory was performed by Dr. Robert Kimura as part of a prior study ( Salt et al., 1995a ). MR specimens were imaged at the Center for In Vivo Microscopy, Duke University, supported by NIH Research Grant P41 RR05959.
PY - 2002/12
Y1 - 2002/12
N2 - The endolymphatic sac is believed to represent one of the primary loci for endolymph volume regulation in the inner ear. Quantitative analysis of physiologic measurements from the endolymphatic sac requires knowledge of the anatomy of the structure, specifically the luminal volume and the variation of cross-sectional area with distance along the sac. Recently techniques have become available to make these measurements. In the present study, fixed, isolated specimens of the guinea pig endolymphatic sac were imaged by high-resolution magnetic resonance microscopy (MRM) or by histological serial sections. Structures were reconstructed and quantified using image analysis software. In specimens imaged by MRM the endolymphatic sac volume, including tissue and lumen, was 359 nl for the intraosseous region and 106 nl for the extraosseous region, totaling 465 nl for the entire structure. The luminal volumes were 131 nl for the intraosseous region and 13 nl for the extraosseous region, totaling 144 nl. In histological specimens the volume, including tissue and lumen, was 414 nl for the intraosseous region and 121 nl for the extraosseous region, totaling 535 nl for the entire structure. The luminal volumes were 152 nl for the intraosseous region and 26 nl for the extraosseous region, totaling 179 nl. Differences in volume estimates obtained by the two methods were not statistically significant and variation was dominated by inter-specimen variation. Pooling the data, the total volume of the endolymphatic sac in the guinea pig including tissue and lumen was 506 nl (S.D. 100, n=17) and the volume of the lumen was 169 nl (S.D. 48, n=14).
AB - The endolymphatic sac is believed to represent one of the primary loci for endolymph volume regulation in the inner ear. Quantitative analysis of physiologic measurements from the endolymphatic sac requires knowledge of the anatomy of the structure, specifically the luminal volume and the variation of cross-sectional area with distance along the sac. Recently techniques have become available to make these measurements. In the present study, fixed, isolated specimens of the guinea pig endolymphatic sac were imaged by high-resolution magnetic resonance microscopy (MRM) or by histological serial sections. Structures were reconstructed and quantified using image analysis software. In specimens imaged by MRM the endolymphatic sac volume, including tissue and lumen, was 359 nl for the intraosseous region and 106 nl for the extraosseous region, totaling 465 nl for the entire structure. The luminal volumes were 131 nl for the intraosseous region and 13 nl for the extraosseous region, totaling 144 nl. In histological specimens the volume, including tissue and lumen, was 414 nl for the intraosseous region and 121 nl for the extraosseous region, totaling 535 nl for the entire structure. The luminal volumes were 152 nl for the intraosseous region and 26 nl for the extraosseous region, totaling 179 nl. Differences in volume estimates obtained by the two methods were not statistically significant and variation was dominated by inter-specimen variation. Pooling the data, the total volume of the endolymphatic sac in the guinea pig including tissue and lumen was 506 nl (S.D. 100, n=17) and the volume of the lumen was 169 nl (S.D. 48, n=14).
KW - Endolymph
KW - Endolymphatic sac
UR - http://www.scopus.com/inward/record.url?scp=0036888562&partnerID=8YFLogxK
U2 - 10.1016/S0378-5955(02)00610-X
DO - 10.1016/S0378-5955(02)00610-X
M3 - Article
C2 - 12433391
AN - SCOPUS:0036888562
SN - 0378-5955
VL - 174
SP - 1
EP - 8
JO - Hearing research
JF - Hearing research
IS - 1-2
ER -