Effects of cabergoline and rotigotine on tacrine-induced tremulous jaw movements in rats

Movement disorders associated with acetylcholinesterase inhibitors in Alzheimer's dementia: A systematic review

BACKGROUND

Acetylcholinesterase inhibitors (AChEIs) are widely used in Alzheimer's disease (AD). This study aims to systematically review the literature about movement disorders (MDs) associated with AChEIs for AD, which include donepezil, galantamine, rivastigmine, tacrine, and ipidacrine.

METHODOLOGY

Two reviewers conducted a comprehensive review of relevant studies across six databases, without language restrictions, covering publications from 1992 to 2024.

RESULTS

Overall, 74 studies containing 92 cases were found of MDs related to ACHEIs. The MDs found were Pisa syndrome in 33 patients, parkinsonism in 31, myoclonus in 11, dystonia in 10, dyskinesia in 6, and extrapyramidal symptoms in 1. Regarding the medications, the abnormal movements were associated with donepezil in 62 cases, rivastigmine in 15, galantamine in 10, and tacrine in 5. No case of ipidacrine-induced MD was found. Overall, the most commonly affected sex was the female, accounting for 61.9% of the cases. The mean and median age was 74.1 (standard deviation: 8.9) and 75 years (range: 49-93 years). The MD occurred within 6 months of the starting of AChEI in approximately 70% of the patients. Furthermore, the full recovery of the MD after the main management was noticed within 6 months in about 80% of the patients. About 86.3% of the individuals fully recovered after treatment, which included AChEI discontinuation, dose adjustment, and prescription of additional therapy.

CONCLUSIONS

The occurrence of tacrine-induced tremor indicated a potential predisposition to movement disorders associated with AChEI therapy. Based on the drug class side effect profile, it is possible that future studies may observe abnormal movements with other AChEIs.

Therapeutic Effect of a Novel Chimeric Molecule Targeting Both Somatostatin and Dopamine Receptors on Growth Hormone-Secreting Pituitary Adenomas

BACKGROUND

Acromegaly is a rare disease primarily caused by growth hormone (GH)-secreting pituitary adenomas, and its treatment is costly. Moreover, some patients are unresponsive to treatment. Hence, there are increasing efforts to develop new drugs with improved effectiveness for this disease. BIM23B065 is a novel chimeric molecule that acts on both somatostatin and dopamine receptors. This study aimed to investigate the effects of BIM23B065 compared with those of a somatostatin receptor analog and a dopamine agonist.

METHODS

The effects of BIM23B065 on the proliferation, GH and insulin-like growth factor-1 (IGF-1) levels, and extracellular signal-regulated kinase (ERK) 1/2 and cyclic AMP response element binding (CREB) phosphorylation of GH3 cells were investigated with MTS assay, enzyme-linked immunosorbent assay, and Western blotting, respectively. The dosage and treatment duration of BIM23B065 were tested in animal models of GH-secreting pituitary adenoma. The effect of BIM23B065 (3 mg/kg/day) on changes in IGF-1 levels before and after treatment was further investigated.

RESULTS

In vitro, BIM23B065 treatment decreased GH release in the culture media and downregulated ERK 1/2 and CREB phosphorylation to 22% and 26%, respectively. In vivo, IGF-1 expression decreased to 50 % after 4 weeks of treatment with BIM23B065 using an osmotic pump implant. Moreover, magnetic resonance imaging results showed that the tumor size decreased significantly following treatment with BIM23B065 for 4 weeks.

CONCLUSION

The novel chimeric molecule was effective in decreasing IGF-1 and GH levels and may serve as an effective therapeutic agent for acromegaly.

A new outlook on cholinergic interneurons in Parkinson's disease and L-DOPA-induced dyskinesia

Traditionally, dopamine (DA) and acetylcholine (ACh) striatal systems were considered antagonistic and imbalances or aberrant signaling between these neurotransmitter systems could be detrimental to basal ganglia activity and pursuant motor function, such as in Parkinson's disease (PD) and L-DOPA-induced dyskinesia (LID). Herein, we discuss the involvement of cholinergic interneurons (ChIs) in striatally-mediated movement in a healthy, parkinsonian, and dyskinetic state. ChIs integrate numerous neurotransmitter signals using intrinsic glutamate, serotonin, and DA receptors and convey the appropriate transmission onto nearby muscarinic and nicotinic ACh receptors to produce movement. In PD, severe DA depletion causes abnormal rises in ChI activity which promote striatal signaling to attenuate normal movement. When treating PD with L-DOPA, hyperkinetic side effects, or LID, develop due to increased striatal DA; however, the role of ChIs and ACh transmission, until recently has been unclear. Fortunately, new technology and pharmacological agents have facilitated understanding of ChI function and ACh signaling in the context of LID, thus offering new opportunities to modify existing and discover future therapeutic strategies in movement disorders.