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Vagusstoff (literally translated from German as "Vagus Substance") refers to the substance released by stimulation of the vagus nerve which causes a reduction in the heart rate. Discovered in 1921 by physiologist Otto Loewi , vagusstoff was the first confirmation of chemical synaptic transmission and the first neurotransmitter ever discovered.
His experiment was iconic because it was the first to demonstrate the endogenous release of a chemical substance that could cause a response in the absence of electrical stimulation. It paved the way for the understanding that the electrical signaling event (action potential) causes a chemical event (release of neurotransmitter from synapses ...
Vagusstoff transmitted inhibition from the vagus nerves, and Acceleransstoff transmitted stimulation from the sympathetic nerves to the heart. [31] Loewi took some years to commit himself with respect to the nature of the Stoffe , but in 1926 he was sure that Vagusstoff was acetylcholine, writing in 1936 [ 32 ] "I no longer hesitate to identify ...
Loewi described the substance released by the vagus nerve as vagusstoff, which was later found to be acetylcholine. Drugs that inhibit the muscarinic receptors ( anticholinergics ) such as atropine and scopolamine , are called vagolytic because they inhibit the action of the vagus nerve on the heart, gastrointestinal tract, and other organs.
The 1921 discovery by Otto Loewi of Vagusstoff using frog hearts resulted in the identification of acetylcholine as the first neurotransmitter. [10] Enkephalin using bioassays such as the mouse vas deferens as a bioassay. [11] Nitric oxide using both assays of bull retractor penis and aortic ring. [12]
"Behavioral sink" is a term invented by ethologist John B. Calhoun to describe a collapse in behavior that can result from overpopulation.The term and concept derive from a series of over-population experiments Calhoun conducted on Norway rats between 1958 and 1962. [1]
The LSD experiments are perhaps the best documented of the psychochemical experiments of the time, garnering at least two significant independent reports. [ 4 ] [ 33 ] [ 34 ] LSD is a Psychedelic drug that acts as a dopamine and serotonin agonist [ 35 ] [ 36 ] precipitating a hallucinogenic effect, leading to hallucinations , euphoria , and a ...
The experiments start with a dog's heart, attached to a set of tubes to serve as substitutes for the great vessels. Using a system to supply it with blood, the heart beats in the same manner as if it were inside a living organism. The film then shows a lung in a tray, which is operated by bellows that oxygenate the blood being sent to the heart ...