Light microscopic immunocytochemistry (ICC) of the central nucleus (CA) of the rat amygdaloid complex revealed two populations of corticotropin releasing factor (CRF) immunoreactive (IR) neuronal perikarya and terminals. Perikarya were isolated within the centrolateral (CL) subdivision of the CA (76.6% of all CRF-IR perikarya in the CA) and the centromedial subdivision of the CA (23.4% of total). CRF-IR fibers were occasionally observed within the stria terminals (ST) while a dense population of CRF-IR terminals was located in the central lateral capsular (CLC) subdivision of CA. In the CLC, CRF-IR terminals were observed to gather around clear circular areas suggesting an association with immunonegative neurons. Tyrosine hydroxylase (TH) IR in the CA was restricted to terminals. These terminals were virtually absent from the CLC, but densely accumulated in the CL where the greatest number of CRF-IR cell bodies were located. In the CL and CM, TH-IR terminals were observed in close association with clear areas that appeared to be unstained neurons. Double ICC for CRF and TH revealed that many of the TH-IR terminals were closely associated with CRF-IR neurons suggesting that synaptic contact might be present Electron microscopic ICC of the CA revealed that CRF-IR neuronal processes were spineless and were contacted by many asymmetric axodendritic synapses which occasionally contained dense cored vesicles while CRF-IR neurons were contacted by numerous mostly symmetric terminals. In the CLC, CRF-IR terminals were observed making numerous synaptic contact with immunonegative structures. Many of these terminals contained clear round vesicles of 50nm diameter and occasional dense cored vesicles that were approximately 100nm in diameter. Double EM ICC for CRF and TH revealed TH-IR terminals making both symmetric and asymmetric synaptic contacts with CRF-IR perikarya and denerites. TH-IR terminals contained 50nm clear round vesicles and 100 nm dense cored vesicles The origin or significance of intracentral amygdaloid CRF-IR connections could not be determined in the present study. However, through interconnections with several brainstem autonomic centers as well as the A10 and A9 mesencephalic dopaminergic cell groups, it is possible that the TH to CRF connections described in this work play an important role in directing autonomic responses to stress / acase@tulane.edu
| Identifer | oai:union.ndltd.org:TULANE/oai:http://digitallibrary.tulane.edu/:tulane_24964 |
| Date | January 1990 |
| Contributors | Thomas, Charles Randolph (Author) |
| Publisher | Tulane University |
| Source Sets | Tulane University |
| Language | English |
| Detected Language | English |
| Rights | Access requires a license to the Dissertations and Theses (ProQuest) database., Copyright is in accordance with U.S. Copyright law |
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