Amitriptyline and imipramine inhibit the release of acetylcholine from parasympathetic nerve terminals in the rat iris. 1984

J S Richardson, and T G Mattio, and E Giacobini

The electrically stimulated release of [3H]acetylcholine from the parasympathetic nerve terminals of the rat iris in vitro is increased in a dose-dependent manner by scopolamine but is decreased by the tricyclic antidepressants amitriptyline and imipramine. The increased release in the presence of scopolamine seems to be due to the blockade of a presynaptic muscarinic autoreceptor that, in the drug-free state, inhibits the release of acetylcholine. However, at drug concentrations that should have comparable antimuscarinic potency, the antidepressants inhibit the release of acetylcholine. This suggests that the anticholinergic side effects of the antidepressants may be due to the reduced release of acetylcholine from parasympathetic nerve terminals as well as a possible direct postsynaptic muscarinic receptor blocking action. Whatever the mechanism of this action, the antidepressants do not have the same effect as scopolamine at the presynaptic muscarinic autoreceptor in the rat iris.

UI MeSH Term Description Entries
D007099 Imipramine The prototypical tricyclic antidepressant. It has been used in major depression, dysthymia, bipolar depression, attention-deficit disorders, agoraphobia, and panic disorders. It has less sedative effect than some other members of this therapeutic group. Imidobenzyle,Imizin,4,4'-Methylenebis(3-hydroxy-2-naphthoic acid)-3-(10,11-dihydro-5H-dibenzo(b,f)azepin-5-yl)-N,N-dimethyl-1-propanamine (1:2),Imipramine Hydrochloride,Imipramine Monohydrochloride,Imipramine Pamoate,Janimine,Melipramine,Norchlorimipramine,Pryleugan,Tofranil
D007498 Iris The most anterior portion of the uveal layer, separating the anterior chamber from the posterior. It consists of two layers - the stroma and the pigmented epithelium. Color of the iris depends on the amount of melanin in the stroma on reflection from the pigmented epithelium.
D010275 Parasympathetic Nervous System The craniosacral division of the autonomic nervous system. The cell bodies of the parasympathetic preganglionic fibers are in brain stem nuclei and in the sacral spinal cord. They synapse in cranial autonomic ganglia or in terminal ganglia near target organs. The parasympathetic nervous system generally acts to conserve resources and restore homeostasis, often with effects reciprocal to the sympathetic nervous system. Nervous System, Parasympathetic,Nervous Systems, Parasympathetic,Parasympathetic Nervous Systems,System, Parasympathetic Nervous,Systems, Parasympathetic Nervous
D011950 Receptors, Cholinergic Cell surface proteins that bind acetylcholine with high affinity and trigger intracellular changes influencing the behavior of cells. Cholinergic receptors are divided into two major classes, muscarinic and nicotinic, based originally on their affinity for nicotine and muscarine. Each group is further subdivided based on pharmacology, location, mode of action, and/or molecular biology. ACh Receptor,Acetylcholine Receptor,Acetylcholine Receptors,Cholinergic Receptor,Cholinergic Receptors,Cholinoceptive Sites,Cholinoceptor,Cholinoceptors,Receptors, Acetylcholine,ACh Receptors,Receptors, ACh,Receptor, ACh,Receptor, Acetylcholine,Receptor, Cholinergic,Sites, Cholinoceptive
D000109 Acetylcholine A neurotransmitter found at neuromuscular junctions, autonomic ganglia, parasympathetic effector junctions, a subset of sympathetic effector junctions, and at many sites in the central nervous system. 2-(Acetyloxy)-N,N,N-trimethylethanaminium,Acetilcolina Cusi,Acetylcholine Bromide,Acetylcholine Chloride,Acetylcholine Fluoride,Acetylcholine Hydroxide,Acetylcholine Iodide,Acetylcholine L-Tartrate,Acetylcholine Perchlorate,Acetylcholine Picrate,Acetylcholine Picrate (1:1),Acetylcholine Sulfate (1:1),Bromoacetylcholine,Chloroacetylcholine,Miochol,Acetylcholine L Tartrate,Bromide, Acetylcholine,Cusi, Acetilcolina,Fluoride, Acetylcholine,Hydroxide, Acetylcholine,Iodide, Acetylcholine,L-Tartrate, Acetylcholine,Perchlorate, Acetylcholine
D000639 Amitriptyline Tricyclic antidepressant with anticholinergic and sedative properties. It appears to prevent the re-uptake of norepinephrine and serotonin at nerve terminals, thus potentiating the action of these neurotransmitters. Amitriptyline also appears to antagonize cholinergic and alpha-1 adrenergic responses to bioactive amines. Amineurin,Amitrip,Amitriptylin Beta,Amitriptylin Desitin,Amitriptylin RPh,Amitriptylin-Neuraxpharm,Amitriptyline Hydrochloride,Amitrol,Anapsique,Apo-Amitriptyline,Damilen,Domical,Elavil,Endep,Laroxyl,Lentizol,Novoprotect,Saroten,Sarotex,Syneudon,Triptafen,Tryptanol,Tryptine,Tryptizol,Amitriptylin Neuraxpharm,Apo Amitriptyline,Desitin, Amitriptylin,RPh, Amitriptylin
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
D012601 Scopolamine An alkaloid from SOLANACEAE, especially DATURA and SCOPOLIA. Scopolamine and its quaternary derivatives act as antimuscarinics like ATROPINE, but may have more central nervous system effects. Its many uses include an anesthetic premedication, the treatment of URINARY INCONTINENCE and MOTION SICKNESS, an antispasmodic, and a mydriatic and cycloplegic. Hyoscine,Scopolamine Hydrobromide,Boro-Scopol,Isopto Hyoscine,Kwells,Scoburen,Scopace,Scopoderm TTS,Scopolamine Cooper,Transderm Scop,Transderm-V,Travacalm HO,Vorigeno,Boro Scopol,Transderm V
D051381 Rats The common name for the genus Rattus. Rattus,Rats, Laboratory,Rats, Norway,Rattus norvegicus,Laboratory Rat,Laboratory Rats,Norway Rat,Norway Rats,Rat,Rat, Laboratory,Rat, Norway,norvegicus, Rattus

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