ISSN:
1432-2072
Keywords:
Developing rat
;
Immobility reaction
;
Neurotoxins
;
5,7-Dihydroxytryptamine
;
6-Hydroxydopamine
;
Serotonin
;
Dopamine
;
Noradrenaline
;
Open field behavior
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Abstract The ontogenetic development of the audiogenic immobility reaction (freezing) was studied in rats given intracisternal injections of the neurotoxins 5,7-dihydroxytryptamine (5,7-DHT), 25 μg, or 6-hydroxydopamine (6-OHDA), 100 μg, neonatally (Day 1). The duration of the freezing response was strongly reduced in the 5,7-DHT-treated rats between 20–30 days of age, when normal animals show very prolonged responses. During the same period increased motor activity was observed in the 6-OHDA-treated rats while only a slight reduction of the freezing response was noted. Biochemical analyses performed on brains from animals 35 days of age showed a selective reduction (about 50%) of whole brain levels of serotonin in the 5,7-DHT-treated rats, while the noradrenaline levels were selectively reduced by about 60% in the 6-OHDA rats. A longitudinal investigation on the effects of neonatal treatment with 5,7-DHT showed a persistent selective reduction of the whole brain level of serotonin up to at least 90 days of age. Since 5,7-DHT mainly affects the serotonergic pathways, the results suggest that the disturbances noted in the ontogeny of the freezing response may be due to interference with the developing serotonergic system.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00436168
