Perinatal, not adult, hypothyroidism suppresses dopaminergic axon sprouting in the deafferented olfactory tubercle of adult rat
✍ Scribed by Dr. Z. Gottesfeld; C. J. Garcia; R. B. Chronister
- Publisher
- John Wiley and Sons
- Year
- 1987
- Tongue
- English
- Weight
- 656 KB
- Volume
- 18
- Category
- Article
- ISSN
- 0360-4012
No coin nor oath required. For personal study only.
✦ Synopsis
We reported recently that chronic thyroid deficiency INTRODUCTION in rat, beginning in utero and terminating after ma-Experimental and clinical documentations have inturity, suppresses lesion-induced Central catecholamdicated that thyroid hormones have their most Critical inergic axon sprouting in the adult brain [Gottesfeld influence on the brain during the late fetal and early et al, 19851. The present work was undertaken to postnatal period of development [see recent reviews by quent neuronal sprouting. during this so-called "critical period," unless treated in Thyroid hormones deficiency was induced in rats early infancy, leads to permanent mental retardation and define the critical period of hypothyroidism on subse-Nunez 1984a,b; Legrand, 19841. Thus, hypothyroidism by methimazole during (a) gestational days 8-21 (20 behavioral abnormalities. These deficits are thought to mg/kg/day in the drinking water); @) postnatal days be partly associated with defects in myelination, neuronal ture animal for weeks (20 mg/kg/day in the drinking mones deficiency during the perinatal period [Eayrs, 1-15 (0.2 or 0.4 mg/pup/day; i-p-), or (C) in the magrowth, and synaptogenesis ensuing from thyroid horwater). The olfactory tubercles (OTS) were used as a 1961; Ford and Cramer 19771. The mature central nermodel to study sprouting of dopaminergic (DA) nerve vous system appears to be less vulnerable to altered terminals, by Olfactory bulbectomY* thyroid status, but if injured it becomes sensitive to thyin each group received lesions or sham operations as roid hormones [Kiernan, 19791. Consequently, an in-