What choline ester is used to increase salivary secretions?

Cevimeline is the correct answer because it is specifically designed to stimulate muscarinic receptors in the salivary glands, enhancing salivary secretion. This makes it particularly effective for treating dry mouth conditions, such as Sjögren's syndrome, where patients experience diminished saliva due to auto-immune destruction of the salivary glands.

While other choline esters like Bethanechol, Carbachol, and Methacholine have various applications, they do not primarily target salivary gland function. Bethanechol is primarily used for urinary retention and gastrointestinal motility issues. Carbachol is mainly utilized in managing glaucoma due to its effects on the eye. Methacholine is primarily used in bronchial challenge tests for diagnosing asthma and does not have a significant role in stimulating salivation. Therefore, Cevimeline stands out for its specific action in increasing salivary secretions.