Osmotic stimulation induces changes in the expression of beta-adrenergic receptors and nuclear volume of astrocytes in supraoptic nucleus of the rat.
The influence of osmotic stimulation on the density of beta-adrenoceptor binding sites in the rat supraoptic nucleus (SON) was studied by quantitative autoradiography using 125I-cyanopindolol (ICYP). Increased density of beta-adrenoceptor binding sites was observed in osmotically stimulated rats and also after the suppression of neuronal activation by rehydration of animals. This was mainly due to a significant increase in the concentration of beta 2 binding sites. The overexpression of beta-adrenoceptors occurred concomitantly with nuclear expansion in SON astrocytes. Moreover, the higher concentration of beta-adrenoceptors observed in the ventral portion of the SON largely coincided with the area that showed intense GFAP-immunostaining. These results provide indirect evidence of an astrocytic location of beta-adrenoceptors and also of beta-adrenergic mediation in the structural and functional changes of SON astrocytes.
Lafarga
M
M
Department of Anatomy and Cell Biology, Faculty of Medicine, Santander, Spain.
Berciano
M T
MT
Del Olmo
E
E
Andres
M A
MA
Pazos
A
A
D000818:Animals; D001253:Astrocytes / Q000378:metabolism*; D001345:Autoradiography; D002467:Cell Nucleus / Q000378:metabolism*; D005455:Fluorescent Antibody Technique; D005904:Glial Fibrillary Acidic Protein / Q000276:immunology / Q000378:metabolism; D020120:Iodocyanopindolol; D008297:Male; D009473:Neuronal Plasticity; D009994:Osmolar Concentration; D010869:Pindolol / Q000031:analogs & derivatives; D010904:Pituitary Gland, Posterior / Q000166:cytology / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D011943:Receptors, Adrenergic, beta / Q000096:biosynthesis*; D013495:Supraoptic Nucleus / Q000166:cytology / Q000378:metabolism*
D005904:Glial Fibrillary Acidic Protein; D011943:Receptors, Adrenergic, beta; D020120:Iodocyanopindolol; D010869:Pindolol