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Biomedical subjects

B Vitiello

Publications and source records attributed to B Vitiello.

75 records · Page 5Linked to original sources
PubMed1984

Pharmacokinetics and metabolism of premazepam, a new potential anxiolytic, in humans.

Premazepam, a pyrrolodiazepine with potential anxiolytic properties, behaves as a partial antagonist to diazepam in animal tests. Its pharmacokinetics and metabolism were studied in four healthy volunteers. After oral administration of 30 mg [6-14C] premazepam, the plasma levels of total radioactivity reached maximum concentrations 1-4 h (mean 2 h) following administration. The plasma curve was described by an open one-compartment model, and half-life was 11.5 +/- 1.3 h. Levels of the unchanged compound accounted for about 80% of the total radioactivity up to 24 h. Half-life of the unchanged compound was 7.9 +/- 1.2 h. On the average, 89.6% of the administered radioactivity was recovered in the urine and 2.3% in the feces during the 5 days following administration. Unchanged premazepam accounted for about 70% of the total radioactivity excreted in the urine. Of the three metabolites identified in the urine, none was active in vitro in displacing 3H-diazepam from its forebrain receptors in the rat, indicating that only the parent compound has definite pharmacologic activity.

Adult↗
PubMedDate not supplied

Increased cognitive sensitivity to scopolamine with age and a perspective on the scopolamine model.

18 older normal volunteers (mean age = 66.5 +/- 7.9 years) and 46 younger volunteers (mean age = 27.0 +/- 6.1 years) were administered the anticholinergic drug scopolamine (0.5 mg i.v.) followed by a battery of cognitive tests evaluating attention, learning and memory. The older subjects were significantly more impaired than the younger by scopolamine on some tests of learning and memory. This increased sensitivity of the older group to scopolamine is consistent with studies in animals and humans showing decreased cholinergic system function with age. The findings also indicate that age is an important variable to consider in using the scopolamine model of memory impairment. The cognitive impairment caused by scopolamine in younger subjects in this and prior studies is similar to some, but not all aspects of the impairment which occurs in normal aging. Scopolamine also caused impairments on digit span and word fluency tasks, which are not consistent with normal aging changes. In the older group of subjects, scopolamine produced aspects of the cognitive impairment which occurs in AD on tests of episodic memory and learning, vigilance-attention, category retrieval, digit span, and number of intrusions. Other areas of cognition that are of relevance to aging and AD such as psychomotor speed, praxis, concept formation and remote memory were not evaluated in this study. Some of these are being evaluated in ongoing studies, along with additional and more specific tests of retrieval from knowledge memory, implicit memory and attention. The scopolamine model has provided a fruitful pharmacologic starting point for the study of a number of cognitive operations. The idea of dissecting apart aspects of memory systems pharmacologically depends on the availability of neurochemically specific drugs and on the specificity and sensitivity of neuropsychological tests for distinct cognitive operations or domains. Further studies using such tools will aid not only in the understanding of the impairments which occur in aging and in AD, but also of the conceptualization of memory and other cognitive operations and ultimately the physiological mechanisms involved in memory and learning.

Acetylcholine↗