Biomaterial Database

Stimulation of pulmonary J receptors by an enkephalin-analog. 1981

H N Sapru, and R N Willette, and A J Krieger

Respiratory and cardiovascular actions of a stable enkephalin-analog (EA), D-met2-pro5-enkephalinamide, were studied in decerebrate male Wistar rats. Injection of a small dose of EA (10 micrograms/kg) into the right atrium produced apnea, bradycardia and hypotension within 1 to 2 sec. These effects lasted for 2 to 4 sec. Apnea was followed by a period of fast and shallow breathing which lasted for 7 to 10 min. The decrease in heart rate and mean blood pressure was 26 +/- 3% (S.E.) and 12 +/- 1.5% (S.E.), respectively. Higher doses of EA used in this study (100,500 and 1,000 micrograms/kg, right atrium) produced similar responses. However, the durations of apnea and fst and shallow breathing and magnitudes of bradycardia and hypotension were greater with the higher doses. Bilateral vagotomy (low in the neck) abolished these effects. These actions are typical of pulmonary J receptor stimulation. Nerve recording experiments in artificially ventilated rats showed that interruption of vagal innervation to the lungs abolished the EA-induced cessation of phrenic nerve activity (apnea), increased frequency of phrenic nerve bursts (fast breathing) and decreased spike activity in each burst (shallow breathing). These results suggested that EA stimulated lung sensory receptors. Of the known lung sensory receptors (stretch, irritant and J. receptors), only pulmonary J receptors are known to produce apnea, bradycardia and hypotension. Direct recordings from pulmonary J receptor fibers in thin filaments of vagus confirmed that EA stimulates these receptors.

UI	MeSH Term	Description	Entries
D008297	Male		Males
D010791	Phrenic Nerve	The motor nerve of the diaphragm. The phrenic nerve fibers originate in the cervical spinal column (mostly C4) and travel through the cervical plexus to the diaphragm.	Nerve, Phrenic,Nerves, Phrenic,Phrenic Nerves
D011651	Pulmonary Artery	The short wide vessel arising from the conus arteriosus of the right ventricle and conveying unaerated blood to the lungs.	Arteries, Pulmonary,Artery, Pulmonary,Pulmonary Arteries
D011984	Sensory Receptor Cells	Specialized afferent neurons capable of transducing sensory stimuli into NERVE IMPULSES to be transmitted to the CENTRAL NERVOUS SYSTEM. Sometimes sensory receptors for external stimuli are called exteroceptors; for internal stimuli are called interoceptors and proprioceptors.	Nerve Endings, Sensory,Neurons, Sensory,Neuroreceptors,Receptors, Neural,Neural Receptors,Receptors, Sensory,Sensory Neurons,Sensory Receptors,Nerve Ending, Sensory,Neural Receptor,Neuron, Sensory,Neuroreceptor,Receptor Cell, Sensory,Receptor Cells, Sensory,Receptor, Neural,Receptor, Sensory,Sensory Nerve Ending,Sensory Nerve Endings,Sensory Neuron,Sensory Receptor,Sensory Receptor Cell
D012119	Respiration	The act of breathing with the LUNGS, consisting of INHALATION, or the taking into the lungs of the ambient air, and of EXHALATION, or the expelling of the modified air which contains more CARBON DIOXIDE than the air taken in (Blakiston's Gould Medical Dictionary, 4th ed.). This does not include tissue respiration (	Breathing
D001794	Blood Pressure	PRESSURE of the BLOOD on the ARTERIES and other BLOOD VESSELS.	Systolic Pressure,Diastolic Pressure,Pulse Pressure,Pressure, Blood,Pressure, Diastolic,Pressure, Pulse,Pressure, Systolic,Pressures, Systolic
D004723	Endorphins	One of the three major groups of endogenous opioid peptides. They are large peptides derived from the PRO-OPIOMELANOCORTIN precursor. The known members of this group are alpha-, beta-, and gamma-endorphin. The term endorphin is also sometimes used to refer to all opioid peptides, but the narrower sense is used here; OPIOID PEPTIDES is used for the broader group.	Endorphin
D004744	Enkephalin, Methionine	One of the endogenous pentapeptides with morphine-like activity. It differs from LEU-ENKEPHALIN by the amino acid METHIONINE in position 5. Its first four amino acid sequence is identical to the tetrapeptide sequence at the N-terminal of BETA-ENDORPHIN.	Methionine Enkephalin,5-Methionine Enkephalin,Met(5)-Enkephalin,Met-Enkephalin,5 Methionine Enkephalin,Enkephalin, 5-Methionine,Met Enkephalin
D004745	Enkephalins	One of the three major families of endogenous opioid peptides. The enkephalins are pentapeptides that are widespread in the central and peripheral nervous systems and in the adrenal medulla.	Enkephalin
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia