Tachyphylaxis
Eledoisin
Methysergide
An ergot derivative that is a congener of LYSERGIC ACID DIETHYLAMIDE. It antagonizes the effects of serotonin in blood vessels and gastrointestinal smooth muscle, but has few of the properties of other ergot alkaloids. Methysergide is used prophylactically in migraine and other vascular headaches and to antagonize serotonin in the carcinoid syndrome.
Ganglionic Stimulants
Agents that mimic neural transmission by stimulation of the nicotinic receptors on postganglionic autonomic neurons. Drugs that indirectly augment ganglionic transmission by increasing the release or slowing the breakdown of acetylcholine or by non-nicotinic effects on postganglionic neurons are not included here nor are the nonspecific cholinergic agonists.
Amaryllidaceae Alkaloids
Alkaloids derived from TYRAMINE combined with 3,4-dihydroxybenzaldehyde via a norbelladine pathway, including GALANTAMINE, lycorine and crinine. They are found in the Amaryllidaceae (LILIACEAE) plant family.
Metiamide
A histamine H2 receptor antagonist that is used as an anti-ulcer agent.
Pentagastrin
Tyramine
An indirect sympathomimetic. Tyramine does not directly activate adrenergic receptors, but it can serve as a substrate for adrenergic uptake systems and monoamine oxidase so it prolongs the actions of adrenergic transmitters. It also provokes transmitter release from adrenergic terminals. Tyramine may be a neurotransmitter in some invertebrate nervous systems.
Histamine
Decamethonium Compounds
Methacholine Compounds
Dimethylphenylpiperazinium Iodide
Atropine
An alkaloid, originally from Atropa belladonna, but found in other plants, mainly SOLANACEAE. Hyoscyamine is the 3(S)-endo isomer of atropine.