Mediation by neurotensin-receptors of effects of neurotensin on self-stimulation of the medial prefrontal cortex.
1 Intracortical microinjections of neurotensin (NT) selectively decreased intracranial self-stimulation (ICSS) of the medial prefrontal cortex in the rat. 2 To elucidate whether this effect is mediated by NT receptors or by the formation of NT-dopamine complexes, we investigated the effects on ICSS of intracortical microinjections of neurotensin (1-11), an NT fragment that forms extracellular complexes with dopamine but does not bind to NT receptors. 3 We also studied the effects of the peripheral administration of SR 48692, a selective antagonist of NT receptors, on the inhibition of ICSS produced by the intracortical administration of NT. 4 Unilateral microinjections of neurotensin (1-11) at doses of 10, 20 and 40 nmol into the medial prefrontal cortex did not change the basal ICSS rate of this area. 5 The intraperitoneal administration of SR 48692 at doses of 0.08 and 0.16 mg kg-1 30 min before microinjection of 10 nmol of NT into the medial prefrontal cortex, antagonized the inhibition of ICSS produced by the neuropeptide. 6 These results demonstrate that the inhibitory effect of NT on ICSS is mediated by NT receptors.
Fernández
R
R
Departamento de Fisiología, Facultad de Medicina, Universidad de Granada, Spain.
Sabater
R
R
Sáez
J A
JA
Montes
R
R
Alba
F
F
Ferrer
J M
JM
D000818:Animals; D008297:Male; D008845:Microinjections; D009496:Neurotensin / Q000494:pharmacology*; D017397:Prefrontal Cortex / Q000502:physiology* / Q000648:ultrastructure*; D011720:Pyrazoles / Q000494:pharmacology; D011804:Quinolines / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D018028:Receptors, Neurotensin / Q000037:antagonists & inhibitors / Q000187:drug effects* / Q000502:physiology*
D011720:Pyrazoles; D011804:Quinolines; D018028:Receptors, Neurotensin; C079087:SR 48692; D009496:Neurotensin