Peripheral muscarinic effects
Peripheral muscarinic effects
The peripheral cholinergic system is mainly responsible for muscarinic effects. This system consists of two pathways, known as the autonomic and parasympathetic pathway. The autonomic pathway affects the heart rate, respiration, blood pressure, digestion, and other involuntary processes. The parasympathetic pathway is associated with motor, cognitive, and emotional functions.
The muscarinic effects of the peripheral cholinergic system are numerous, and vary among different tissues. Here are some of the most important muscarinic effects caused by acetylcholine on the peripheral tissues:
- Cardiovascular system: Acetylcholine on the peripheral cholinergic receptors causes a decrease in the heart rate, an increase in the diastolic blood pressure, and a decrease in the total peripheral resistance, resulting in decreased blood flow.
- Gastrointestinal tract: Acetylcholine on the peripheral cholinergic receptors causes stimulation of intestinal movement, increased production of digestive enzymes, and increased secretions from the pancreas.
- Skeletal muscles: Acetylcholine on the peripheral cholinergic receptors causes an increase in muscle tension, an increased rate of contractility, and an increased firing rate of motor units.
- Respiratory system: Acetylcholine on the peripheral cholinergic receptors causes an increase in tidal volume, an increase in the respiratory rate, and a decrease in the ventilatory oxygen response.
- Nervous system: Acetylcholine on the peripheral cholinergic receptors causes an increase in neuronal excitability, decreased neurotransmitter release, and increased motor function.
These are just a few of the many muscarinic effects caused by acetylcholine on the peripheral cholinergic system. While muscarinic effects can be beneficial, in some cases the effects can be dangerous, especially when excessive levels of acetylcholine are released. For this reason, it is important to monitor the levels of acetylcholine in the body and ensure that levels remain in a therapeutically beneficial range.