THE HYPOTHALAMIC SEROTONERGIC SYSTEM: EFFECTS OF CHEMICAL NEUROTOXINS IN THE RAT.
Item
-
Title
-
THE HYPOTHALAMIC SEROTONERGIC SYSTEM: EFFECTS OF CHEMICAL NEUROTOXINS IN THE RAT.
-
Identifier
-
AAI8401931
-
identifier
-
8401931
-
Creator
-
FRANKFURT, MAYA.
-
Contributor
-
Efrain Azmitia
-
Date
-
1983
-
Language
-
English
-
Publisher
-
City University of New York.
-
Subject
-
Biology, Anatomy
-
Abstract
-
The hypothalamic serotonergic system of the rat was studied following intracerebral injection of 5,7-dihydroxtryptamine (5,7-DHT). Changes in serotonin (5-HT) immunocytochemical staining, ('3)H5-HT uptake and 5-HT levels in the hypothalamus and lordosis behavior were assessed over time.;Three days after unilateral injection of 5,7-DHT (3 ug free base) into the dorsolateral hypothalamus 5-HT immunoreactive-(IR) fibers were swollen and darkly stained in the ipsilateral medial forebrain bundle (MFB). In the contralateral hypothalamus some degeneration was apparent, however this was generally restricted to the area adjacent to the fornix. There was a gradual decrease in the 5-HT-IR fiber density in the ipsilateral MFB 3-19 days post lesion. The ipsilateral periventricular and medial hypothalamic areas contained virtually no 5-HT-IR fibers 7-30 days post lesion. Sprouting 5-HT-IR fibers were abundant 12-19 days post lesion and 30 days post lesion there was a normal or supranormal density of 5-HT-IR fibers in the MFB, however other areas were not reinnervated. Fifty days post lesion there was an apparent hyperinnervation of 5-HT fibers ipsilateral and contralateral to the injection of 5,7-DHT as compared to sham injected animals.;The morphological data are supported by changes in ('3)H5-HT uptake and 5-HT. 5-HT levels and ('3)H5-HT uptake are lowest 7 days post lesion and there is a gradual recovery in both ('3)H5-HT uptake and 5-HT levels 30-50 days post lesion.;Unilateral injection of 5,7-DHT (3 ug free base) into the dorsolateral hypothalamus resulted in the removal of a group of 5-HT-IR cells which had been observed in initial immunocytochemical studies. The injection of 6-hydroxydopamine (3 ug free base) into the dorsolateral hypothalamus or 5,7-DHT into the rostral midbrain had no effect on the staining of this cell group. Furthermore, a patch of thin 5-HT-IR fibers ventrolateral to the 5-HT-IR cells was apparent after removal of the ascending 5-HT fibers by injection of 5,7-DHT into the rostral midbrain.;Lordosis behavior was rapidly facilitated following bilateral injection of 5,7-DHT (5 ug free base) into the dorsolateral hypothalamus. The facilitation observed continued until 42-46 days post lesion. Preliminary immunocytochemical evidence indicates that the transplantation of fetal raphe tissue results in a rapid reversal of the facilitation in lordosis observed after 5,7-DHT.
-
Type
-
dissertation
-
Source
-
PQT Legacy CUNY.xlsx
-
degree
-
Ph.D.
-
Program
-
Biomedical Sciences
