Intracisternal 5,7-dihydroxytryptamine lesions in neonatal and adult rats: comparison of response to 5-hydroxytryptophan.
There have been few previous studies of the functional significance of 5,7-dihydroxytryptamine (5,7-DHT) lesions made in neonatal rats. To study the role of serotonin (5-HT) in recovery of function, rat pups and adult rats were injected intracisternally with 5,7-DHT or saline and challenged acutely with the 5-HT precursor 5-hydroxytryptophan (5-HTP) 4 weeks later as a test of behavioral supersensitivity. Compared to 5,7-DHT lesions in adults, neonatal lesions induced significantly greater 5-HT depletions in brainstem, but 5-HT depletions in other regions were not significantly different in the two groups. Rats with early 5,7-DHT lesions displayed supersensitive behavioral responses to 5-HTP, consisting of all the component myoclonic-serotonergic behaviors seen in rats with 5,7-DHT lesions made as adults. However, there was significantly less 5-HTP-evoked head weaving, truncal myoclonus and shaking behavior in rats treated with 5,7-DHT as neonates. Body weight was reduced both in rats with early and late 5,7-DHT lesions, but reduction persisted in rats with early lesions. These data indicate overall similarity with some differences between neurochemical and behavioral effects of early and late 5,7-DHT lesions made by the intracisternal route. They suggest that recovery mechanisms did not occur or failed to reverse the neurochemical or behavioral consequences of early 5,7-DHT lesions.
Pranzatelli
M R
MR
Department of Neurology, College of Physicians and Surgeons, Columbia University, New York, N.Y.
Dollison
A M
AM
Hlibczuk
V
V
D015116:5,7-Dihydroxytryptamine / Q000494:pharmacology*; D006916:5-Hydroxytryptophan / Q000494:pharmacology*; D000367:Age Factors; D000818:Animals; D001522:Behavior, Animal; D001835:Body Weight; D001927:Brain Diseases / Q000139:chemically induced / Q000378:metabolism*; D004102:Dihydroxytryptamines / Q000494:pharmacology*; D009207:Myoclonus; D051381:Rats; D011919:Rats, Inbred Strains; D012701:Serotonin / Q000378:metabolism / Q000502:physiology*
D004102:Dihydroxytryptamines; D015116:5,7-Dihydroxytryptamine; D012701:Serotonin; D006916:5-Hydroxytryptophan