Involvement of brain dopamine systems on neurotensin-induced protection against stress gastric lesions.
We have previously demonstrated that intracisternal (i.c.) administration of neurotensin (NT), a brain and gastrointestinal tridecapeptide, potently inhibits gastric ulcer formation induced by cold-restraint stress (CRS) in rats. This study evaluated the effect of i.c. NT (17.9 nmol) or vehicle (10 microliter of 0.9% NaCl) on the development of CRS-induced gastric ulcers and on dopamine (DA) concentrations and DA turnover (DOPAC/DA) in selected brain regions after 0, 1, 2 and 3 h of CRS. As anticipated, and in confirmation of previous findings, NT significantly reduced the incidence and severity of CRS gastric ulcers in a time-dependent manner. Neurotensin significantly decreased DA concentration and DA turnover in the striatum. In the nucleus accumbens, however, NT produced a decrease in DA concentration and a concomitant increase in DA turnover after 2 and 3 h of CRS. No significant effects of brain NT on DA concentration and DA turnover were observed in the hypothalamus or olfactory tubercles. These findings suggest that the anti-ulcer effect of brain NT may be mediated, at least in part, by a differential activation of the mesolimbic and nigrostriatal DA systems.
D000818:Animals; D001921:Brain / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D002946:Cisterna Magna; D004298:Dopamine / Q000378:metabolism*; D007267:Injections; D008297:Male; D009496:Neurotensin / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D013276:Stomach Ulcer / Q000378:metabolism* / Q000517:prevention & control; D013312:Stress, Physiological / Q000150:complications / Q000378:metabolism*; D013997:Time Factors
D009496:Neurotensin; D004298:Dopamine