Tap. Roeling et al., BEHAVIORAL-RESPONSES OF BICUCCULLINE METHIODIDE INJECTIONS INTO THE VENTRAL HYPOTHALAMUS OF FREELY MOVING, SOCIALLY INTERACTING RATS, Brain research, 615(1), 1993, pp. 121-127
Several studies, using electrical stimulation of parts of the hypothal
amus, have shown, that different parts of the hypothalamus yield diffe
rent behavioural responses upon stimulation. In order to differentiate
between stimulation of neuronal cell bodies and passing fibres and to
investigate the role of GABA in hypothalamically elicited behaviour,
25 local injections with bicucculline methiodide, a GABA antagonist, (
35 ng/0.2 mul) were performed in the ventral parts of the hypothalamus
of 16 freely moving rats in a social environment. A cannula system wa
s used that allowed injection without interruption of the ongoing soci
al interactions. Digging, gnawing, drinking and attack behaviour were
elicited in different animals. By plotting the behavioural responses o
f the animals into a detailed hypothalamic atlas, we assessed the hypo
thalamic distribution of the elicited behavioural responses. A number
of injections elicited a combination of two or three different respons
es, probably due to diffusion of the substance, thus disinhibiting mor
e than one behavioural system. Our results are in general agreement wi
th previous electrical stimulation data and show that, in an overlappi
ng pattern, different populations of neurons are involved in the elici
tation of digging, gnawing, drinking and attack behaviour. In the hypo
thalamus, a tonic GABAergic inhibition of neurons involved in the disp
lay of these types of behaviour appears to exist.