title: Characterization of thyroid hormone effect on the visual system of the adult rat.
abstract: To characterize the effect of thyroid hormone on the central nervous system in adult rats, we recorded evoked potentials by photic (VEP) and electrical stimulation in normal, thyroidectomized (Tx) and T3- or T4-supplemented (Tx-T3, Tx-T4) male adult rats under pentobarbital anesthesia. The latencies of VEPs recorded in the visual cortex (VC) and lateral geniculate nucleus (LGN), and the b-waves of the electroretinograms (ERG) of these three groups were compared. A significant prolongation of the latency of VEP by photic stimulation (flash light intensity 2J, 0.2 Hz) in the VC was observed 14 to 28 days after thyroidectomy (27.9 +/- 0.4 vs. 33.4 +/- 0.43 msec, p < 0.01). Similar prolongations were also observed when those of the VEP in the LGN and the b-wave of the ERG were compared to those of normal rats (22.4 +/- 0.37 vs. 27.3 +/- 0.41 msec, p < 0.01; 21.8 +/- 0.21 vs. 25.3 +/- 0.41 msec, p < 0.01, respectively). The prolonged latencies observed in the VC, LGN, and ERG-b-wave were partially normalized 24 hr after T3 supplement (50 micrograms/kg, sc) and fairly restored to normal levels by 48 hr after T4 injection (100 micrograms/kg sc). The VEP latencies in the LGN and VC showed a positive correlation with the b-wave latency of the ERG in these three groups.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Department of Physiology, Medical School, Gunma University, Maebashi, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Takeda
authors.forename: N
authors.initials: N
authors.lastname: Onoda
authors.forename: M
authors.initials: M
authors.lastname: Suzuki
mesh_terms: D000818:Animals; D004558:Electric Stimulation; D004596:Electroretinography / Q000187:drug effects*; D005074:Evoked Potentials, Visual / Q000187:drug effects* / Q000502:physiology; D008297:Male; D009900:Optic Nerve / Q000187:drug effects / Q000502:physiology; D010775:Photic Stimulation; D051381:Rats; D017208:Rats, Wistar; D013961:Thyroid Gland / Q000378:metabolism / Q000601:surgery; D013963:Thyroid Hormones / Q000494:pharmacology*; D013965:Thyroidectomy; D013974:Thyroxine / Q000097:blood / Q000494:pharmacology
chemical_list: D013963:Thyroid Hormones; D013974:Thyroxine