TY - JOUR
T1 - Effects of triiodothyronine and propylthiouracil on regeneration of catecholaminergic nerve terminals in the paraventricular hypothalamic nucleus of the adult rat
AU - Hoovler, Dennis W.
AU - Hwang, Bang H.
AU - Demers, Laurence M.
N1 - Funding Information:
CNS-centml nervous system, 6-OHDA-6-hy-PVN-paraventricular hypothalamic nucleus, T3- triiodothyronine. ’ This work was supported by a fund from the Department of Anatomy, The Milton S. Hershey Medical Center. The authors are grateful for the secretarial assistance of Ms. Doris Lineweaver. The present address of Dr. Hoovler is Department of Physiology, George Washington University School of Medicine, Washington, D.C. 20037. Please address reprint requests to Bang H. Hwang, Ph.D., Department of Anatomy, The Milton S. Hershey Medical Center, Box 850, Hershey, PA 17033.
PY - 1985/7
Y1 - 1985/7
N2 - Effects of triiodothyronine and the antithyroid drug, propylthiouracil, on regeneration of catecholaminergic nerve terminals in the paraventricular hypothalamic nucleus of adult rats were studied. Lesions were produced by 6-hydroxydopamine neurotoxin and then the animals were treated with triiodothyronine or propylthiouracil inducing hyperthyroidism or hypothyroidism, respectively, as determined by radioimmunoassay. Although catecholaminergic varicosities increased with time in the paraventricular hypothalamic nucleus of rats after lesion, fluorescent microscopic quantitation showed no statistical difference in their number between rats treated with triiodothyronine and the vehicle for as long as 56 days. Furthermore, electron microscopic quantitation at 56 days postlesion showed no significant difference between the triiodothyronine-treated and control rats in terms of the density, proportion, size, types of synapses, and synaptic frequency of catecholaminergic nerve terminals. There were growth cones in the paraventricular hypothalamic nucleus, suggesting growth activity after lesion. However, we found that exogenous administration of large doses of triiodothyronine at 25 μg/kg had little effect on the enhancement of regeneration of central catecholaminergic terminals after their destruction by 6-hydroxydopamine.
AB - Effects of triiodothyronine and the antithyroid drug, propylthiouracil, on regeneration of catecholaminergic nerve terminals in the paraventricular hypothalamic nucleus of adult rats were studied. Lesions were produced by 6-hydroxydopamine neurotoxin and then the animals were treated with triiodothyronine or propylthiouracil inducing hyperthyroidism or hypothyroidism, respectively, as determined by radioimmunoassay. Although catecholaminergic varicosities increased with time in the paraventricular hypothalamic nucleus of rats after lesion, fluorescent microscopic quantitation showed no statistical difference in their number between rats treated with triiodothyronine and the vehicle for as long as 56 days. Furthermore, electron microscopic quantitation at 56 days postlesion showed no significant difference between the triiodothyronine-treated and control rats in terms of the density, proportion, size, types of synapses, and synaptic frequency of catecholaminergic nerve terminals. There were growth cones in the paraventricular hypothalamic nucleus, suggesting growth activity after lesion. However, we found that exogenous administration of large doses of triiodothyronine at 25 μg/kg had little effect on the enhancement of regeneration of central catecholaminergic terminals after their destruction by 6-hydroxydopamine.
UR - http://www.scopus.com/inward/record.url?scp=0021833246&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0021833246&partnerID=8YFLogxK
U2 - 10.1016/0014-4886(85)90270-5
DO - 10.1016/0014-4886(85)90270-5
M3 - Article
C2 - 3924645
AN - SCOPUS:0021833246
SN - 0014-4886
VL - 89
SP - 123
EP - 133
JO - Experimental Neurology
JF - Experimental Neurology
IS - 1
ER -