The effect of ergot alkaloids ergosinine, dihydroergosine and dihydroergotamine on neurotransmission and contractility of the isolated ileum of the guinea-pig

Effect of ergot-alkaloid dihydroergosine on the immune reaction and plasma corticosterone in rats

Ergot-alkaloid dihydroergosine, a potential antidepressive and anxiolytic drug, suppressed humoral and cellular immune reaction in rats, if given in a single injection (2-100 mg/kg) 1 hour after immunization. Plasma corticosterone levels were decreased upon assay of the immune response, 5 or 8 days following treatment.

Inhibitory influence of dihydroergosine on the aggressiveness of rats and mice

Fifty mg/kg of ergot alkaloid dihydroergosine (DHESN) inhibited the mouse-killing behavior of isolated male rats, while 10 mg/kg did not. This effect of DHESN (50 mg/kg) lasted for 24 hr. When an additional injection of DHESN (50 mg/kg) was given to mouse-killer rats 6 days following the first, the mouse-killing behavior was again inhibited. The effect of the second drug injection also persisted for 24 hr and was accompanied by an increased concentration of 5-HT in the raphe nuclei and hypothalamus and by a decreased concentration of GABA in the olfactory bulbs. DHESN also inhibited aggressiveness in isolated mice. Two hr following the administration of 10 mg/kg DHESN the fighting was inhibited in 46% of pairs tested, while 50 mg/kg abolished it completely. The effect of 50 mg/kg lasted 24 hr. These results, showing the antiaggressive effects of DHESN, support our previous suggestion that DHESN might presumably be a new antidepressant, and suggest that besides the serotoninergic, the GABA-ergic system might also be involved in the modification of behavior induced by this drug.

Effects of the potential antidepressant dihydroergosine in rats forced to swim: influence on plasma corticosterone

The potential antidepressant properties of the ergot alkaloid dihydroergosine (DHESN) were studied in rats forced to swim in a restricted space. DHESN (50 mg/kg, intraperitoneally) reduced the duration of immobility in rats forced to swim 1 hr after administration. This effect was still present after 48 hr, but 7 hr. In non-swimming rats, the same dose of DHESN increased the plasma corticosterone concentration when administered 1 hr prior to sacrifice, but was without effect 48 hr after administration. In rats forced to swim, DHESN elicited two opposite effects. One hr following a single administration, it increased plasma secretion of corticosterone, whereas administered 48 hr prior to forced swimming, it decreased plasma corticosterone. These results, along with our previous data, give evidence that DHESN might possess antidepressant properties.

Effect of dihydroergosine (DHESN) on the serotoninergic system and behaviour: is DHESN a new antidepressive agent?

Acute (50.0 mg/kg) and repeated (0.1-10.0 mg/kg) administration of dihydroergosine (DHESN) to rats over 5 days lowered the concentration of 5-HIAA in the brain. DHESN given acutely increased the brain 5-HT in p-CPA-treated animals and diminished the probenecid-induced increase in brain 5-HIAA. In pargyline-treated rats DHESN enhanced the 5-HT/5-HIAA ratio. DHESN administered to rats repeatedly over 5 days decreased the level of 5-HT in blood platelets, and in vitro at concentrations of 10(-4) M and 10(-3) M inhibited the uptake of [14C]-5-HT in platelets. DHESN (10.0-100.0 mg/kg) potentiated the 5-HT syndrome produced in rats by pargyline and 5-HTP. This potentiation was blocked with cyproheptadine but not with haloperidol. DHESN (1.0 and 10.0 mg/kg) lowered the locomotor activity of rats and 10.0 mg/kg DHESN also reduced the duration of immobility in rats forced to swim in a restricted space. The results indicate that DHESN, like antidepressants, decreases the turnover of serotonin in the brain and potentiates the 5-HT-mediated behaviour. This might suggest that the drug should be further investigated for its potential antidepressive properties.