Drugs Aging. 1997 Sep ;11 (3):206-28 9303280 [Cited: 2]

Nicotinic system involvement in Alzheimer's and Parkinson's diseases. Implications for therapeutics.

[My paper] P A Newhouse , A Potter , E D Levin

Advances in our understanding of the structure, function and distribution of nicotinic acetylcholine receptors in the CNS have provided the impetus for new studies examining the role(s) that these receptors and associated processes may play in CNS functions. Further motivation has come from the realisation that such receptors must be involved in the maintenance of cigarette smoking, and from clues provided by studies of degenerative neurological diseases such as Alzheimer's disease and Parkinson's disease, in which the loss of nicotinic receptors has been described. Ongoing investigations of the molecular substructure of central nicotinic receptors and their pharmacology have begun to open up new possibilities for novel CNS therapeutics with nicotinic agents. Exploiting these possibilities will require understanding of the role(s) that these receptor systems play in human cognitive, behavioural, motor and sensory functioning. Clues from careful studies of human cognition are beginning to emerge and will provide direction for studies of potentially therapeutic novel nicotinic agents. Despite the promising results of acute studies, few long term studies with nicotine or nicotinic drugs have been performed in dementing disorders. Thus there is uncertainty as to whether long term nicotinic treatment will provide sustained cognitive benefit. It is even more uncertain whether such cognitive benefit will have a significant clinical impact on patients and their families. To maximise the potential benefit of long term treatment with nicotinic agonists (or other cholinergic drugs), we suggest that drug treatment should be combined with cognitive rehabilitation strategies. This will enable patients and/or their families to focus on the particular cognitive domains that may be improved.

Mesh-terms: Alzheimer Disease, drug therapy; Alzheimer Disease, etiology; Alzheimer Disease, metabolism; Animals; Cognition Disorders, metabolism; Cognition, drug effects; Combined Modality Therapy; Disease Models, Animal; Human; Nicotine, pharmacology; Nicotine, therapeutic use; Nicotinic Agonists, pharmacology; Nicotinic Agonists, therapeutic use; Nicotinic Antagonists, pharmacology; Nicotinic Antagonists, therapeutic use; Parkinson Disease, drug therapy; Parkinson Disease, etiology; Parkinson Disease, metabolism; Receptors, Nicotinic, drug effects; Receptors, Nicotinic, metabolism; Support, Non-U.S. Gov't; Support, U.S. Gov't, P.H.S.;

redline.jpg

Psychopharmacology (Berl). 1999 Apr ;143 (2):158-65 10326778 [Cited: 2]
Four-week nicotine skin patch treatment effects on cognitive performance in Alzheimer's disease.
[My paper] H K White , E D Levin
RATIONALE: Acute nicotine injections have been found to improve attentional performance in patients with Alzheimer's disease (AD), but little is known about chronic nicotine effects. OBJECTIVE: The present study was undertaken to evaluate the clinical and neuropsychological effects of chronic transdermal nicotine in Alzheimer's disease subjects over a 4-week period. METHODS: The double-blind, placebo controlled, cross-over study consisted of two 4-week periods separated by a 2-week washout period. Patients wore the nicotine patch (Nicotrol) for 16 h a day at the following doses: 5 mg/day during week 1, 10 mg/day during weeks 2 and 3 and 5 mg/day during week 4. The eight subjects had mild to moderate AD and were otherwise healthy. RESULTS: Nicotine significantly improved attentional performance as measured by the Conners' continuous performance test (CPT). There was a significant reduction in errors of omission on the CPT which continued throughout the period of chronic nicotine administration. The variability of hit reaction time (reaction time for correct responses) on the CPT was also significantly reduced by chronic nicotine. Nicotine did not improve performance on other tests measuring motor and memory function. CONCLUSIONS: The sustained improvement in attention found in this study with nicotine dermal patches is encouraging. However, the lack of detected effects of nicotine treatment on other cognitive and behavioral domains in this study leaves questions concerning the clinical impact of nicotinic treatment in Alzheimer's disease. The modest size of this study limited statistical power which may have been needed to detect more subtle but clinically significant cognitive effects. Higher doses of nicotine, other nicotinic ligands or combination treatment of nicotine with other therapies may be efficacious for producing broader therapeutic effects.
Mesh-terms: Administration, Cutaneous; Aged; Aged, 80 and over; Alzheimer Disease, drug therapy; Alzheimer Disease, psychology; Attention, drug effects; Cognition, drug effects; Female; Human; Male; Memory, drug effects; Middle Aged; Nicotine, administration & dosage; Nicotine, therapeutic use; Nicotinic Agonists, administration & dosage; Nicotinic Agonists, therapeutic use; Psychomotor Performance, drug effects; Treatment Outcome;

redline.jpg

Widespread Decrease of Nicotinic Acetylcholine Receptors in Parkinson's Disease

redline.jpg

PubMed

Post-mortem studies have demonstrated a substantial loss of nicotinic receptors in Parkinson's disease (PD), which may be at least partially responsible for some of the cognitive, motoric, and behavioral deficits seen in this disorder. Epidemiologic studies have suggested that cigarette smoking is a strong negative risk factor for the development of PD. We have previously shown that blockade of central nicotinic receptors produces cognitive impairment in areas of new learning, short-term memory, and psychomotor slowing with increasing dose sensitivity with age and disease. Studies of acute stimulation of nicotinic receptors in Alzheimer's disease with nicotine and the novel agonist ABT-418 in our laboratory and others have shown improvements in several measures of cognitive function. Prior studies of the effects of nicotine in PD have suggested some improvements in clinical symptomatology. We have begun quantitative studies of both acute and chronic nicotine in PD to assess both cognitive and motor effects. Fifteen (15) nondemented subjects (age 66 +/- 5.3; M/F = 11/4) with early to moderate PD (mean Hoehn-Yahr stage = 1.77; MMSE = 28.6) received a dose-ranging study of intravenous nicotine up to 1.25 microg/kg/min, followed by chronic administration of nicotine by transdermal patch with doses ranging up to 14 mg per day for 2 weeks. Testing occurred both during drug administration and up to 2 months after drug cessation to look for prolonged effects. Preliminary analysis shows improvements after acute nicotine in several areas of cognitive performance, particularly measures such as reaction time, central processing speed, and decreased tracking error. Improvements in attention and semantic retrieval were not seen. After chronic nicotine, improvements were seen in several motor measures suggesting improved extrapyramidal functioning. This appeared to be sustained for up to 1 month after drug. The treatment was well tolerated. Nicotinic stimulation may have promise for improving both cognitive and motor aspects of Parkinson's disease.