Effects of unilateral decortication on beta-adrenergic receptors in the remaining cortex and in the hypothalamus of female rats.
Many experiments have been performed to evaluate the physiological role of catecholaminergic mechanisms in gonadotropin release. The purpose of the present study was to determine the concentration of beta-adrenoreceptors in the remaining (right) cerebral cortex and in right and left hypothalamic halves of hemi-decorticated female rats which exhibited elevated plasma gonadotropin levels as observed previously. The density of beta-receptors was measured using a high-affinity beta-adrenergic ligand, iodocyanopindolol (ICYP). Scatchard estimates were obtained for maximum binding (Bmax fmol/mg of tissues) from pooled cerebral cortical and hypothalamic tissue of animals under several experimental conditions after hemi-decortication and sham operation. There was an increase in beta-adrenoreceptor density in the remaining (right) cerebral cortex at all times examined in hemi-decorticate in comparison with the sham-operated animals (7 days, +10.9%; 21 days, +8.4%; 90 days, +22%; and 90 days plus ovariectomy, +34.8%). The number of beta-adrenoreceptors in the right hypothalamic half in hemi-decorticates decreased at 21 days (-42.20%) and then increased at 90 days (+76.63%) and 90 days plus ovariectomy (+51.75%) when compared with the left hypothalamic half. At the same time there were no significant changes in the sham-operated animals when comparing the receptor density in the right and left hypothalamic halves, respectively. Thus, our results suggest a direct or indirect adrenergic pathway by which the left cortex can influence the right cortex and a crossed pathway to the contralateral hypothalamus changing adrenergic activity which can alter the beta-adrenergic receptor binding capacity in the hypothalamus.
D000818:Animals; D002540:Cerebral Cortex / Q000032:analysis / Q000502:physiology* / Q000648:ultrastructure; D005260:Female; D007839:Functional Laterality / Q000502:physiology*; D007031:Hypothalamus / Q000032:analysis / Q000502:physiology* / Q000648:ultrastructure; D011869:Radioligand Assay; D051381:Rats; D011919:Rats, Inbred Strains; D011943:Receptors, Adrenergic, beta / Q000032:analysis / Q000502:physiology* / Q000648:ultrastructure; D013997:Time Factors
D011943:Receptors, Adrenergic, beta