Actions of derivatives of lysergic acid on the heart of Venus mercenaria.
5-Hydroxytryptamine and a number of (+)-lysergic acid derivatives have been tested on the heart of Venus mercenaria. One group of derivatives was found to increase the amplitude and frequency of heart beat in a manner much like 5-hydroxytryptamine. It included the monoethylamide, diethylamide, propanolamide (ergometrine), butanolamide (methylergometrine) and certain peptide derivatives of lysergic acid without substituents in positions 1 or 2. Of these, lysergic acid diethylamide was the most active. Given sufficient time (up to 4 hr), as little as 10 ml. of 10(-16) M lysergic acid diethylamide produced a maximum increase in amplitude and frequency in about one-half of the 80 hearts on which it was tested. Its action was very slowly reversed by washing, as was true of all lysergic acid derivatives. A second group of lysergic acid derivatives, substituted in positions 1 or 2, had weak excitor action, if any, and specific 5-hydroxytryptamine blocking action. This group consisted of 1-methyl-, 1-acetyl-, and 2-bromo-lysergic acid diethylamide and 1-methyllysergic acid butanolamide (methysergide). Of these, the last showed least signs of excitor action, usually none up to 10(-4) M, and it blocked 5-hydroxytryptamine in a molar ratio of about one to one.
D000818:Animals; D049872:Bivalvia; D006321:Heart / Q000494:pharmacology*; D008237:Lysergic Acid; D008238:Lysergic Acid Diethylamide / Q000494:pharmacology* / Q000031:analogs & derivatives; D049891:Mercenaria; D008784:Methysergide; D008974:Mollusca / Q000494:pharmacology*; D010455:Peptides; D012701:Serotonin; D018536:Venus
D010455:Peptides; D012701:Serotonin; C034985:1-methyllysergic acid butanolamide; D008238:Lysergic Acid Diethylamide; D008237:Lysergic Acid; D008784:Methysergide
HEART/pharmacology; LYSERGIC ACID DIETHYLAMIDE/pharmacology; MOLLUSCA/pharmacology