Understanding the Molecular Basis of 5-HT(4) Receptor Partial Agonists through 3D-QSAR Studies

Alzheimer’s disease (AD) is a neurodegenerative disorder whose prevalence has an incidence in senior citizens. Unfortunately, current pharmacotherapy only offers symptom relief for patients with side effects such as bradycardia, nausea, and vomiting. Therefore, there is a present need to provide other therapeutic alternatives for treatments for these disorders. The 5-HT(4) receptor is an attractive therapeutic target since it has a potential role in central and peripheral nervous system disorders such as AD, irritable bowel syndrome, and gastroparesis. Quantitative structure-activity relationship analysis of a series of 62 active compounds in the 5-HT(4) receptor was carried out in the present work. The structure-activity relationship was estimated using three-dimensional quantitative structure-activity relationship (3D-QSAR) techniques based on these structures’ field molecular (force and Gaussian field). The best force-field QSAR models achieve a value for the coefficient of determination of the training set of R(2)(training) = 0.821, and for the test set R(2)(test) = 0.667, while for Gaussian-field QSAR the training and the test were R(2)(training) = 0.898 and R(2)(test) = 0.695, respectively. The obtained results were validated using a coefficient of correlation of the leave-one-out cross-validation of Q(2)(LOO) = 0.804 and Q(2)(LOO) = 0.886 for force- and Gaussian-field QSAR, respectively. Based on these results, novel 5-HT(4) partial agonists with potential biological activity (pEC(50) 8.209–9.417 for force-field QSAR and 9.111–9.856 for Gaussian-field QSAR) were designed. In addition, for the new analogues, their absorption, distribution, metabolism, excretion, and toxicity properties were also analyzed. The results show that these new derivatives also have reasonable pharmacokinetics and drug-like properties. Our findings suggest novel routes for the design and development of new 5-HT(4) partial agonists.