In the present experiment, the effect of injection of NE into the different areas of hippocampus on the plasma cortisol level and the kind of NE receptor involved were studied in 83 cats anesthetized with Nembutal. The plasma cortisol level was increased following injection of NE into the ventral hippocampus (VHIP), however, there was no significant change when injection was made into dorsal hippocampus. The NE-VHIP effect can be blocked by injection of phentolamine, yohimbine or prazosin but not by propranolol. Thus, these results show that, in the regulation of the plasma cortisol level, the alpha-receptor system of VHIP is more specifically involved.