Cardiovascular and behavioural changes after i.c.v. infusions of histamine and agonists in conscious goat.

Histamine (3 and 10 mumoles) raised the blood pressure in the conscious goat when given i.c.v. but lowered it when given intravenously. The results with 2-PEA support the view that central H1-stimulation raises the blood pressure. However, the results with dimaprit do not exclude the participation of central H2-receptors in the effect of histamine on the blood pressure. It appears that in the goat the stimulation of central H1- and H2-receptors mediates opposite actions on behavour. H1-agonist increased and H2-agonist decreased the general activity of the animal.