The following application is a request for a Mentored Research Scientist Development Award (K0l). The results of this proposal should lead not only to a broader knowledge of anxiety disorders, but also to the intellectual, analytical and technical skills needed to develop into a independent researcher within my chosen career field. The overall objective of the current proposal is to determine the role of corticotropin-releasing factor (CRF) and CRF-like peptides in the basolateral nucleus of the amygdala (BLA) as they relate to anxiety-like behavior. The specific hypotheses to be tested are (1) Acute stimulation of CRF receptors in the BLA by administration of CRF and Urocortin (Ucn) will produce a normal anxiety-like response in rats, (2) Repeated administration of Ucn into the BLA will induce a pathological state of anxiety-like behavior in rats, (3) Repeated administration of Ucn into the BLA of rats will induce intracellular changes similar to that described in calcium calmodulin kinase II-dependent (CaMKII) long-term potentiation (LTP) resulting in a pathological anxiety response, and (4) Repeated activation of CRF receptors in the BLA of rats will produce a long-term facilitation of the anxiety responses resembling a subtype of pathological anxiety, panic disorder. The behavioral paradigms utilized to measure anxiety for each set of experiments will be the social interaction (SI) test, elevated plus maze, and startle response. Microinjections of both agonists and antagonists of CRF receptors will be given into the BLA. The second hypothesis will be addressed by administering repeated injections of sub-threshold doses of a CRF agonist into the BLA. Both Ucn and CRF are able to 'prime' anxiety. Since Ucn has a higher affinity for CRF receptors, it was chosen as the peptide to conduct all the priming studies. To test the third hypothesis, I will administer the NMDA antagonist, AP5, or the non-NMDA antagonist, CNQX, along with Ucn to assess the development of an LTP-like phenomenon. KN-62 or AIP, CaMKII inhibitors, will be administered into the BLA to determine the role of CaMKII in the development of pathological anxiety. In addition, changes in CaMKII phosphorylation states within the BLA will be determined using western blots. Hypothesis four will be tested by determining whether the long term anxiety response seen in Ucn primed rats can be reversed with known anti-panic agents. Since some of my preliminary work has shown that the sodium lactate sensitivity seen in BMI primed animals is mediated via the subfornical organ (SFO, a circumventricular organ)-BLA connection, and it is known that individuals with panic disorder show a sensitivity to sodium lactate, we will examine this pathway in Ucn primed rats. Thus, a group of Ucn primed and sham primed rats will be administered sodium lactate infusions; then, using immunohistochemical staining for the immediate early gene product cfos, the brain areas involved in this abnormal response will be determined. Thus, the study will provide a greater understanding of the underlying neurobiology of pathological anxiety, in particular panic disorder.
| Sajdyk, Tammy J; Johnson, Philip L; Leitermann, Randy J et al. (2008) Neuropeptide Y in the amygdala induces long-term resilience to stress-induced reductions in social responses but not hypothalamic-adrenal-pituitary axis activity or hyperthermia. J Neurosci 28:893-903 |
| Chambers, R Andrews; Sajdyk, Tammy J; Conroy, Susan K et al. (2007) Neonatal amygdala lesions: co-occurring impact on social/fear-related behavior and cocaine sensitization in adult rats. Behav Neurosci 121:1316-27 |
