Pharmacological investigations of the ergot
alkaloid of the group of clavines,
elymoclavine, isolated from Claviceps sp. cp. II showed the following results: The LD50 for mice for 24 h was 350 (228-535) mg/kg and for rats 145 (81-258) mg/kg.
Elymoclavine induced a dose-dependent stereotypy (doses of 2 to 10 mg/kg) in rats and mice which was antagonized by
haloperidol and
pimozide. It prevented the development of
haloperidol catalepsy in rats and produced rotations contralateral to the striatal lesions with
6-OHDA which were antagonized by
pimozide and partly by
cyproheptadine.
Elymoclavine, like
bromocriptine, decreased the plasma level of
prolactin. Furthermore,
elymoclavine increased the exploratory activity of rats in open field; this effect was antagonized by
haloperidol and was essentially influenced by many substances acting on different transmitter systems (NA, DA,
GABA).
Elymoclavine inhibited the
picrotoxin and electroshock convulsive
seizures but potentiated the
pentylenetetrazol ones in mice as these effects were differently influenced by
pimozide,
haloperidol,
5-HTP,
atropine and
phentolamine. 100 and 250 micrograms/kg of
elymoclavine produced a considerable and persisting decrease of the blood pressure in anaesthetized cats. At 1 X 10(-6) M, without producing any per se effect, elyoclavine decreased the contractile effects of
acetylcholine,
nicotine,
BaCl2 and
PGE1 as well as the field electrical stimulation-induced contractions in an isolated segment from guinea-pig ileum. The observed effects of
elymoclavine are mainly due to its
dopaminergic agonist action. It seems, however, that influences on other transmitter receptors also underlie the mechanism of action of this ergot
alkaloid.