Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
4336585 | Journal of Neuroscience Methods | 2007 | 9 Pages |
Abstract
The objective of this study was to develop a method that could reliably determine the arginine vasopressin (AVP) and/or oxytocin (OT) content of individual rat neurohypophysial terminals (NHT) â¥5 μm in diameter, the size used for electrophysiological recordings. We used a commercially available, highly sensitive enzyme-linked immunoassay (ELISA) kit with a sensitivity of 0.25 pg to AVP and of 1.0 pg to OT. The NHT content of AVP (2.21 ± 0.10 pg) was greater than OT (1.77 ± 0.08 pg) and increased with terminal size. AVP-positive terminals (10.2 ± 0.21 μm) were larger in diameter than OT-positive terminals (9.1 ± 0.24 μm). Immunocytochemical techniques indicated that a higher percentage (58%) of smaller terminals contained OT, and that a higher percentage (42%) of larger NHTs were colabeled. Similar percentages of AVP-positive terminals were obtained between immunocytochemical (73%) and ELISA (72%) methods when NHTs were assayed for AVP alone, but there was a higher percentage of OT terminals when using immunocytochemistry (43%) compared to ELISA (26%). The percent of AVP-positive (60%) and OT-positive (18%) terminals decreased when NHT were assayed for both AVP and OT. Therefore, the best method to reliably identify AVP-positive NHTs is to assay only for AVP, since this allows the conclusion that AVP-negative terminals contain only OT.
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Authors
Edward E. Custer, Sonia Ortiz-Miranda, Thomas K. Knott, Randi Rawson, Christian Elvey, Ryan H. Lee, José R. Lemos,