Which of the following effects is associated with muscarinic receptor stimulation?

Muscarinic receptor stimulation primarily leads to a variety of physiological responses that are characteristic of the parasympathetic nervous system. When muscarinic receptors are activated, one significant outcome is the increased gastrointestinal motility. This occurs because muscarinic receptors, when activated by acetylcholine, promote smooth muscle contractions in the gastrointestinal tract, enhancing peristalsis and overall digestive function.

Increased gastrointestinal motility is essential for the proper movement of food through the intestines, aiding in digestion and absorption of nutrients. This effect is opposite to what is generally seen with adrenergic stimulation, which tends to decrease gastrointestinal activity as part of the "fight or flight" response.

The other effects associated with muscarinic receptor stimulation are generally not consistent with what is observed with this type of receptor. For example, stimulation of muscarinic receptors would not lead to increased heart rate, decreased secretions, or increased blood pressure, as these effects align more closely with adrenergic responses mediated by catecholamines like epinephrine and norepinephrine. Thus, understanding the role of muscarinic receptors is crucial for recognizing how they influence physiological processes, particularly in the context of the body's rest and digest functions.