@article {Gutman874, author = {David A. Gutman and Michael J. Owens and Kelly H. Skelton and K. V. Thrivikraman and Charles B. Nemeroff}, title = {The Corticotropin-Releasing Factor1 Receptor Antagonist R121919 Attenuates the Behavioral and Endocrine Responses to Stress}, volume = {304}, number = {2}, pages = {874--880}, year = {2003}, doi = {10.1124/jpet.102.042788}, publisher = {American Society for Pharmacology and Experimental Therapeutics}, abstract = {Corticotropin-releasing factor (CRF) is the major physiological regulator of the hypothalamic-pituitary-adrenal (HPA) axis and serves to coordinate the mammalian endocrine, autonomic, and behavioral responses to stress. Considerable literature from clinical and preclinical data suggests that hypersecretion of hypothalamic and/or extrahypothalamic CRF systems is a major factor in the pathogenesis of affective and anxiety disorders. Based on this premise, a CRF1 receptor antagonist has been hypothesized to possess anxiolytic and/or antidepressant properties. In this study, an acute dose of the lipophilic CRF1 receptor antagonist 3-[6-(dimethylamino)-4-methyl-pyrid-3-yl]-2,5-dimethyl-N,N-dipropyl-pyrazolo[2,3-a]pyrimidin-7-amine (R121919), administered i.v. to rats with surgically implanted jugular cannula 60 min before a 5-min restraint stress, dose dependently attenuated peak plasma adrenocorticopin hormone (ACTH) and corticosterone concentrations by 91 and 75\%, respectively. In a second study, acute administration of R121919 reduced measures of anxiety in a rodent defensive withdrawal paradigm. R121919 dose dependently decreased latency to exit the tube, and total time spent in the tube 60 min after a single subcutaneous administration. In addition, the ACTH and corticosterone response to novelty was decreased by 82 and 97\%, respectively, at the 10-mg/kg dose of R121919. In another study, this dose was associated with approximately an 85\% occupancy of the CRF1 receptor in the cortex measured 75-min postsubcutaneous injection. These data confirm that R121919 acts as a CRF1 receptor antagonist in vivo, attenuates HPA axis responsivity, and possesses anxiolytic properties. The American Society for Pharmacology and Experimental Therapeutics}, issn = {0022-3565}, URL = {https://jpet.aspetjournals.org/content/304/2/874}, eprint = {https://jpet.aspetjournals.org/content/304/2/874.full.pdf}, journal = {Journal of Pharmacology and Experimental Therapeutics} }