Acetylcholinesterase-Positive Innervation Is Present at Undifferentiated Stages of the Sea Turtle Lepidochelis olivacea Embryo Gonads: Implications for Temperature-Dependent Sex Determination

摘要: In embryos of different reptile species, incubation temperature triggers a cascade endocrine events that lead to gonad sex differentiation. The cellular and molecular mechanisms by which sets in motion this process are still controversial. Here, we begin evaluating the possible participation nervous system temperature-dependent determination showing existence origin acetylcholinesterase (AchE)-positive nerve fibers undifferentiated gonads Lepidochelys olivacea (L. olivacea) sea turtle putative male female embryos, along thermosensitive period for (TPSD; stages 20‐27). AChE-positive bundles were readily visualized until developmental stage 24 thereafter. DiI injections confocal imaging showed some these gonadal nerves arise from lower thoracic upper lumbar spinal cord levels, might thus be sensory nature. Because vertebrate is capable integrating itself thermoregulatory responses with no intervention uppermost levels central system, also evaluated maturation during TPSD. was more advanced than when taking place each sex; starts ends earlier embryos. Together observations open possibility innervation derived it could play direct role driving or modulating and/or differentiation, particularly L. J. Comp. Neurol. 410:90‐98, 1999. r 1999 Wiley-Liss, Inc. Indexing terms: vertebrate; sexual differentiation; heterochrony; brain; reptiles