Promnestic Effects of Intranasally Applied Pregnenolone in Rats
Neurobiology of Learning and Memory
Intranasal drug administration, Neuroseroid, Pregnenolone, Memory, Water maze, Object recognition
The neurosteroid pregnenolone (PREG) has been shown to have memory-enhancing and anti-depressant action. The present study addresses the question of whether intranasally applied pregnenolone (IN-PREG) also has promnestic properties in the rat. We examined the effects of IN-PREG at doses of 0.187 and 0.373 mg/kg on memory for objects and their location on learning and retention of escape in a water maze, and on behavior on the elevated plus maze. The main findings were: (a) Pre-trial, but not post trial, administration of IN-PREG facilitated long-term memory in a novel object-preference test and a novel object-location preference test when tested 48 h after dosing. (b) Over the duration of 5 days of extinction trials, after learning to escape onto a hidden platform in a water maze, the animals treated with IN-PREG spent more time in searching for the absent platform, indicating either, or both, superior memory for the former position of the escape platform, or a higher resistance to extinction. (c) Administration of the anticholinergic, scopolamine, disrupted learning to escape from the water maze in the vehicle-treated group. The IN-PREG treated groups exhibited superior escape learning in comparison with vehicle controls, indicating that the treatment countered the scopolamine effect. IN-PREG treatment had no influence on behaviors on the elevated plus maze. Our results demonstrate that IN-PREG is behaviorally active with cognitive enhancing properties comparable to those known from studies employing systemic PREG administration.
Laila Abdel-Hafiz, Owen Y. Chao, Joseph P. Huston, Susanne Nikolaus, Richard E. Spieler, Maria A. de Souza Silva, and Claudia Mattern. 2016. Promnestic Effects of Intranasally Applied Pregnenolone in Rats .Neurobiology of Learning and Memory : 185 -195. https://nsuworks.nova.edu/occ_facarticles/782.