From the Research
J receptors, also known as juxtacapillary receptors, are sensory nerve endings located in the interstitial tissues close to the pulmonary capillaries, and are primarily stimulated by pulmonary congestion, certain chemicals, and increases in interstitial pressure or volume. These receptors play a crucial role in the body's defense mechanism against harmful substances entering the respiratory system, and their activation contributes to the sensation of breathlessness and can influence respiratory patterns in both normal and pathological states 1.
Key Characteristics of J Receptors
- Located in the interstitial tissues close to the pulmonary capillaries
- Primarily stimulated by pulmonary congestion, certain chemicals, and increases in interstitial pressure or volume
- Innervated by unmyelinated C fibers of the vagus nerve
- Particularly sensitive to pulmonary edema, which explains why patients with heart failure often experience dyspnea
Stimulation of J Receptors
- Can be stimulated by pulmonary congestion produced by occlusion of the aorta or left a-v junction, or by injection of alloxan or chlorine into the lungs 2, 3
- Can also be stimulated by increases in interstitial pressure or volume, such as those that occur during muscular exercise 2
- Have a low activation threshold, and can be stimulated by minimal doses of certain chemicals, such as phenyl diguanide (PDG) 1
Clinical Significance of J Receptors
- Play a crucial role in the body's defense mechanism against harmful substances entering the respiratory system
- Activation contributes to the sensation of breathlessness and can influence respiratory patterns in both normal and pathological states
- Understanding J receptor function is important in respiratory physiology and in explaining symptoms in various pulmonary conditions, such as asthma, COPD, and pulmonary edema 4, 5