Effect of AT II on the exploratory behaviour of rats. Interactions with elymoclavine and bromocryptine.

The interaction between the octapeptide angiotensin II (AT II) and the DA-ergic agents (agonists)--the ergotic alkaloid elymoclavine and bromocryptine--during exploratory behaviour was studied in experiments on male albino rats. The changes in the horizontal and vertical activity of the exploratory behaviour and the hole-board activity were investigated using an Opto-Varimex apparatus. AT II, elymoclavine and bromocryptine were applied alone. The frequency of rearing and ambulation was increased with all substances applied (the effect being most pronounced on the 10th min), while the hole-board activity decreased. Elymoclavine potentiates the effect of AT II during exploratory behaviour. The effects of the drugs tested on the exploratory behaviour most probably result from the interaction between AT II receptors, dopamine receptors and through GABA-ergic neurotransmission, in the respective brain zones responsible for behaviour.