Effects of Amygdaloid Lesions on Regional Brain Rna Base Ratios

Eleftheriou, Basil E.; Church, Robert L.; Zolovick, A.J.; Norman, Reid L.; Pattison, M. L.

doi:10.1677/joe.0.0450207

Cited by 4 publications

(3 citation statements)

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“…Evidence has been provided that the amygdala, or certain areas of it, plays an important role in the regulation or modification of sex behavior (1)(2)(3)(4) and gonadal function (5)(6)(7)(8)(9)(10)(11)(12) in different species. That estrogen levels in the blood affect amygdaloid structures is suggested by local EEG changes during estrus (13) and by the fact that estrogen implantation in the amygdaloid region led to a lactogenic response (14) and inhibition of estrogen synthesis (13).…”

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confidence: 99%

“…The localization of estrogen concentrating neurons in the diencephalon and amygdala seem to make up a major portion of the areas of the brain which are involved in the regulation of sex behavior and gonadotropin secretion (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)25). Thus, in view of our findings and the cited evidence in the literature, the concept of "sex center" or "sex centers" seems no longer satisfactory ( 15).…”

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confidence: 99%

“…diol in these labeled neurons with stimulation of RNA and protein synthesis, similar to peripheral target tissues. Fluctuations of RNA concentration in different brain areas depending on the state of the estrous cycle have been described (1 1) and actinomycin D has been shown to nullify the suppressive effect of estrogen on the plasma LH surge in ovariectomized animals (26) ~ The autoradiographic data in conjunction with evidence from lesion and hormone implant experiments suggest that the estrogen-neurons are sites for the production of hormonal messenger, probably releasing or inhibiting factors relevant to gonadal (5)(6)(7)(8)(9)(10)(11)(12)(13)25) and mammary function (14) as well as sex behavior (1)(2)(3)(4). I t is noteworthy that the concentrations of estrogen-neurons are in close proximity to ventrally located portions of the ventricles.…”

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confidence: 99%

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Estradiol Concentrating Neurons in the Amygdala

Stumpf

Sar

1971

Experimental Biology and Medicine

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Evidence has been provided that the amygdala, or certain areas of it, plays an important role in the regulation or modification of sex behavior (1-4) and gonadal function (5-12) in different species. That estrogen levels in the blood affect amygdaloid structures is suggested by local EEG changes during estrus (13) and by the fact that estrogen implantation in the amygdaloid region led to a lactogenic response (14) and inhibition of estrogen synthesis (13). The implication of amygdaloid structures in estrogenneuron systems (15) can be more directly demonstrated and topographically defined by autoradiography with 3H-estradiol. The technique of dry-mount au toradiography has been applied to provide a precise anatomical definition of estradiol "feedback" areas of the hypothalamus ( 16). This information was hitherto unobtainable using lesion, electrical stimulation, or implantation techniques. Since the topography of estradiol concentrating neurons in the preoptic region and hypothalamus corresponds to the terminations of stria terminalis fibers ( 16), estrogen concentrating neurons could be expected in the amygdala (1 7) at the sites of origin of this fiber tract.iiaterials and Methods. This report is based upon observations in nine rats. Four 24-day-old immature, intact female and male, three mature ovariectomized (48 hr prior to experiment) and two intact mature male Sprague-Dawley rats were injected subcutaneously with a dose of 0.1 to 0.2 pg/lOO g of body weight, of 6,7-3H-estradiol-l 7/3, (sp act, 208 pCi/pg) dissolved in isotonic saline, and sacrificed 1 hr afterwards. The low dose of 0.1 pg of 3H-estradiol was selected in order to remain in a physiologic range; this however, required photographic exposure times of 1This study was supported by PHS Grant AM- 12,649. the autoradiograms between 6 and 8 months. The exposure times required in order to demonstrate concentration of radioactivity in neurons of the amygdala are the same as for neurons of the preoptic and basal tuberal region of the hypothalamus. In comparable radioassay studies radioactivity has been reported to be retained and concentrated i,n the hypothalamus and in the amygdala and has been identified as 3H-estradiol-17P in the hypothalamus (18). This, in connection with the similarity in exposure times, strongly suggest that the silver grains over the nuclei of neurons of the amygdala represent estradiol. The autoradiograms were prepared at 1 hr after the injection of 3H-estradiol since maximal uptake exists in target tissues at this time. Two to 3 mm3 pieces of brain containing amygdala were excised, placed on a tissue holder, and frozen in liquified propane. Two micron serial frozen sections were cut in a cryostat (Harris Mfg. Co., Cambridge, Mass.) and freeze-dried (Thermovac Industries Corp., Copiague, N.Y.). The freezedried, unfixed and unembedded sections were dry-mounted on photographic emulsion coated slides for au toradiographic exposure. The dry-mount technique, which excludes the use of solvents and therefore avoids known sources of d...

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