Retrograde facilitation of verbal memory by trihexyphenidyl in healthy elderly
with and without the APOE epsilon4 allele.
Author(s): Pomara N, Yi L, Belzer K, Facelle TM, Willoughby LM, Sidtis JJ.
Affiliation(s): The Geriatric Psychiatry Program, Nathan Kline Institute for Psychiatric
Research, Orangeburg, NY 10962, United States. Pomara@nki.rfmh.org
Publication date & source: 2010, Eur Neuropsychopharmacol. , 20(7):467-72
Retrograde facilitation (RF) of information learned prior to acute oral
administration of trihexyphenidyl, a preferential muscarinic M1 receptor
antagonist which impairs new learning, was studied in 24 healthy elderly
subjects. The relationship between the RF induced by this anticholinergic drug
and the APOE epsilon4 allele was also examined. Acute adverse performance effects
of trihexyphenidyl (1- and 2mg) were determined using the Buschke Selective
Reminding Test administered pre-drug and at 1, 2.5, and 5h post-drug. Recall of
pre-drug words at the end of the fifth hour neuropsychological assessment
(end-of-session recall) was of primary interest. Words studied before drug
administration were better recalled following 2mg trihexyphenidyl compared to
placebo, and this RF effect was not affected by the APOE epsilon4 allele. Better
recall of pre-drug words following 2-mg trihexyphenidyl was associated with a
greater amnestic effect of this dose. Our findings demonstrated that RF induced
by trihexyphenidyl was related to anterograde amnestic effects of the drug and
resulted in part from drug-induced reduction of retroactive interference.
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