Biomaterial Database

Muscarinic receptor regulation of synaptic transmission in airway parasympathetic ganglia. 1996

A C Myers, and B J Undem

Division of Clinical Immunology, Johns Hopkins Asthma and Allergy Center, Baltimore, Maryland 21224, USA.

Muscarinic receptor regulation of synaptic transmission in guinea pig bronchial parasympathetic ganglia was evaluated with the use of intracellular recording of the intrinsic ganglion neurons. Methacholine (1 microM) decreased the amplitude of vagus nerve-stimulated fast excitatory postsynaptic potentials (fEPSP) by 33 and 46% (at 0.8 and 8.0 Hz, respectively) but had no effect on the amplitude of the depolarizations evoked by a bath-applied nicotinic receptor agonist. Methoctramine (1 microM) inhibited methacholine's effect on fEPSP but alone did not influence the magnitude of the fEPSP evoked by vagus nerve stimulation. Methacholine (10 microM) depolarized a subpopulation of neurons (approximately 4 mV), which was blocked by pirenzepine (0.1 microM). In other neurons, either no effect or a small (1-5 mV) hyperpolarization was noted. Cholinergic contractions of bronchial smooth muscle elicited by electrical field stimulation were potentiated by methoctramine to the same extent as those evoked by vagus nerve (preganglionic) stimulation. The data indicate that M2 receptor activation can lead to inhibition of presynaptic acetylcholine release and consequently a significant inhibition of synaptic transmission in bronchial parasympathetic ganglia. The physiological role of this neuromodulatory effect appears limited, however, when studied in the in vitro setting.

UI	MeSH Term	Description	Entries
D008297	Male		Males
D009130	Muscle, Smooth	Unstriated and unstriped muscle, one of the muscles of the internal organs, blood vessels, hair follicles, etc. Contractile elements are elongated, usually spindle-shaped cells with centrally located nuclei. Smooth muscle fibers are bound together into sheets or bundles by reticular fibers and frequently elastic nets are also abundant. (From Stedman, 25th ed)	Muscle, Involuntary,Smooth Muscle,Involuntary Muscle,Involuntary Muscles,Muscles, Involuntary,Muscles, Smooth,Smooth Muscles
D009435	Synaptic Transmission	The communication from a NEURON to a target (neuron, muscle, or secretory cell) across a SYNAPSE. In chemical synaptic transmission, the presynaptic neuron releases a NEUROTRANSMITTER that diffuses across the synaptic cleft and binds to specific synaptic receptors, activating them. The activated receptors modulate specific ion channels and/or second-messenger systems in the postsynaptic cell. In electrical synaptic transmission, electrical signals are communicated as an ionic current flow across ELECTRICAL SYNAPSES.	Neural Transmission,Neurotransmission,Transmission, Neural,Transmission, Synaptic
D010276	Parasympatholytics	Agents that inhibit the actions of the parasympathetic nervous system. The major group of drugs used therapeutically for this purpose is the MUSCARINIC ANTAGONISTS.	Antispasmodic,Antispasmodic Agent,Antispasmodic Drug,Antispasmodics,Parasympathetic-Blocking Agent,Parasympathetic-Blocking Agents,Parasympatholytic,Parasympatholytic Agent,Parasympatholytic Drug,Spasmolytic,Spasmolytics,Antispasmodic Agents,Antispasmodic Drugs,Antispasmodic Effect,Antispasmodic Effects,Parasympatholytic Agents,Parasympatholytic Drugs,Parasympatholytic Effect,Parasympatholytic Effects,Agent, Antispasmodic,Agent, Parasympathetic-Blocking,Agent, Parasympatholytic,Agents, Antispasmodic,Agents, Parasympathetic-Blocking,Agents, Parasympatholytic,Drug, Antispasmodic,Drug, Parasympatholytic,Drugs, Antispasmodic,Drugs, Parasympatholytic,Effect, Antispasmodic,Effect, Parasympatholytic,Effects, Antispasmodic,Effects, Parasympatholytic,Parasympathetic Blocking Agent,Parasympathetic Blocking Agents
D010890	Pirenzepine	An antimuscarinic agent that inhibits gastric secretion at lower doses than are required to affect gastrointestinal motility, salivary, central nervous system, cardiovascular, ocular, and urinary function. It promotes the healing of duodenal ulcers and due to its cytoprotective action is beneficial in the prevention of duodenal ulcer recurrence. It also potentiates the effect of other antiulcer agents such as CIMETIDINE and RANITIDINE. It is generally well tolerated by patients.	Gastrotsepin,Gastrozepin,L-S 519,LS-519,Piren-Basan,Pirenzepin,Pirenzepin Von Ct,Pirenzepin-Ratiopharm,Pirenzepine Dihydrochloride,Pyrenzepine,Ulcoprotect,Ulgescum,Dihydrochloride, Pirenzepine,LS 519,LS519,Piren Basan,Pirenzepin Ratiopharm,Von Ct, Pirenzepin
D011976	Receptors, Muscarinic	One of the two major classes of cholinergic receptors. Muscarinic receptors were originally defined by their preference for MUSCARINE over NICOTINE. There are several subtypes (usually M1, M2, M3....) that are characterized by their cellular actions, pharmacology, and molecular biology.	Muscarinic Acetylcholine Receptors,Muscarinic Receptors,Muscarinic Acetylcholine Receptor,Muscarinic Receptor,Acetylcholine Receptor, Muscarinic,Acetylcholine Receptors, Muscarinic,Receptor, Muscarinic,Receptor, Muscarinic Acetylcholine,Receptors, Muscarinic Acetylcholine
D001980	Bronchi	The larger air passages of the lungs arising from the terminal bifurcation of the TRACHEA. They include the largest two primary bronchi which branch out into secondary bronchi, and tertiary bronchi which extend into BRONCHIOLES and PULMONARY ALVEOLI.	Primary Bronchi,Primary Bronchus,Secondary Bronchi,Secondary Bronchus,Tertiary Bronchi,Tertiary Bronchus,Bronchi, Primary,Bronchi, Secondary,Bronchi, Tertiary,Bronchus,Bronchus, Primary,Bronchus, Secondary,Bronchus, Tertiary
D003959	Diamines	Organic chemicals which have two amino groups in an aliphatic chain.	Diamine
D004558	Electric Stimulation	Use of electric potential or currents to elicit biological responses.	Stimulation, Electric,Electrical Stimulation,Electric Stimulations,Electrical Stimulations,Stimulation, Electrical,Stimulations, Electric,Stimulations, Electrical
D005726	Ganglia, Parasympathetic	Ganglia of the parasympathetic nervous system, including the ciliary, pterygopalatine, submandibular, and otic ganglia in the cranial region and intrinsic (terminal) ganglia associated with target organs in the thorax and abdomen.	Parasympathetic Ganglia,Ciliary Ganglion,Ganglion, Parasympathetic,Otic Ganglia,Pterygopalatine Ganglia,Submandibular Ganglia,Ciliary Ganglions,Ganglia, Otic,Ganglia, Pterygopalatine,Ganglia, Submandibular,Ganglias, Otic,Ganglias, Pterygopalatine,Ganglias, Submandibular,Ganglion, Ciliary,Ganglions, Ciliary,Otic Ganglias,Parasympathetic Ganglion,Pterygopalatine Ganglias,Submandibular Ganglias