Evidence for positive allosteric modulation of cognitive-enhancing effects of nicotine by low-dose galantamine in rats

Recent Advances in the Discovery of Nicotinic Acetylcholine Receptor Allosteric Modulators

Positive allosteric modulators (PAMs), negative allosteric modulators (NAMs), silent agonists, allosteric activating PAMs and neutral or silent allosteric modulators are compounds capable of modulating the nicotinic receptor by interacting at allosteric modulatory sites distinct from the orthosteric sites. This survey is focused on the compounds that have been shown or have been designed to interact with nicotinic receptors as allosteric modulators of different subtypes, mainly α7 and α4β2. Minimal chemical changes can cause a different pharmacological profile, which can then lead to the design of selective modulators. Experimental evidence supports the use of allosteric modulators as therapeutic tools for neurological and non-neurological conditions.

Galantamine tethered hydrogel as a novel therapeutic target for streptozotocin-induced Alzheimer's disease in Wistar rats

Amyloid-β (Aβ) plaque formation, neuronal cell death, and cognitive impairment are the unique symptoms of Alzheimer's disease (AD). No single step remedy is available to treat AD, so the present study aimed to improve the drugability and minimize the abnormal behavioral and biochemical activities in streptozotocin (STZ) induced AD experimental Wistar rats. In particular, we explored the utilization of methacrylated gelatin (GelMA), which is a biopolymeric hydrogel that mimics the natural tissue environment. The synthesized biopolymeric gel contained the drug galantamine (Gal). Investigations were conducted to evaluate the behavioral activities of STZ-induced AD experimental rats under STZ ​+ ​GelMA ​+ ​Gal treatment. The experimental groups comprised the control and STZ, STZ ​+ ​GelMA, STZ ​+ ​Gal, and STZ ​+ ​GelMA ​+ ​Gal (10 ​mg/kg) treated rats. Intracerebroventricular STZ ensures cognitive decline in terms of an increase in the escape latency period, with a decrease in the spontaneous alteration of behavioral activities. Our results indicated decrease Aβ aggregation in the hydrogel-based drug treatment group and significant decreases in the levels of acetylcholinesterase and lipid peroxidation (p ​< ​0.001). In addition, the glutathione and superoxide dismutase activities appeared to be improved in the STZ ​+ ​GelMA ​+ ​Gal group compared with the other treatment groups. Furthermore, histopathological and immunohistochemical experiments showed that the GelMA ​+ ​Gal treated AD rats exhibited significantly improved behavioral and biochemical activities compared with the STZ treated AD rats. Therefore, STZ ​+ ​GelMA ​+ ​Gal administration from the pre-plaque stage may have a potential clinical application in the prevention of AD. Thus, we conclude that hydrogel-based Gal drugs are efficient at decreasing Aβ aggregation and improving the neuroinflammatory process, antioxidant activity, and neuronal growth.

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Hydrogel-based drug treatment normalized cognitive deficit sin ICV-STZ rats with AD.

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Hydrogel-based drug treatment enhanced behavioral and biochemical activities in AD-induced rats.

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Hydrogel-based drug treatment increased memory performance and neuronal growth in rats with AD.

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Antioxidant potential of hydrogel-tethered Gal blocked apoptosis in AD-induced rats.