Regulation of adrenergic receptors in intraocular hippocampal transplants: role of noradrenergic innervation.
Hippocampal tissue transplanted into the anterior chamber of the eye offers a unique system in which development can be studied in the absence of the noradrenergic innervation. This system was used to determine the extent to which noradrenergic innervation regulates the development of adrenergic receptors. In addition to examining single denervated transplants, transplants grown with innervation from the superior cervical ganglia of the host rat or from locus coeruleus cotransplants were also examined to determine whether the source of norepinephrine and extent of innervation in oculo regulate the development and density of adrenergic receptors. In vitro autoradiographic analysis of ligand binding to both alpha 1- and beta-adrenergic receptors with 125I-BE 2254 and 125I-pindolol, respectively, was used to characterize adrenergic receptors in the intraocular transplants. Quantitative analysis of the receptors showed an up-regulation of both alpha 1- and beta-adrenergic receptors in tissue grown in the absence of norepinephrine, but in general there was not a high degree of correlation between norepinephrine content and receptor density. Although high-performance liquid chromatography (HPLC) analysis of catecholamines revealed higher than normal amounts of norepinephrine in hippocampal transplants innervated by the superior cervical ganglia or a locus coeruleus cotransplant, the density of alpha 1 and beta receptors was quite comparable with values found in the literature for normal adult hippocampus. These results suggest that the relationship between receptor number and density of innervation may differ significantly from what is observed in response to pharmacological manipulation of norepinephrine systems in the adult brain.
Mynlieff
M
M
Department of Physiology, Colorado State University, Fort Collins 80523.
Curella
P
P
Zahniser
N R
NR
Gerhardt
G A
GA
Seiger
A
A
Dunwiddie
T V
TV
D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology; D000818:Animals; D001345:Autoradiography; D001679:Biogenic Amines / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D005260:Female; D006624:Hippocampus / Q000502:physiology* / Q000637:transplantation; D007700:Kinetics; D009419:Nerve Tissue Proteins / Q000378:metabolism; D009638:Norepinephrine / Q000502:physiology*; D009799:Ocular Physiological Phenomena; D010627:Phenethylamines / Q000494:pharmacology; D010869:Pindolol / Q000494:pharmacology; D011247:Pregnancy; D051381:Rats; D011919:Rats, Inbred Strains; D011941:Receptors, Adrenergic / Q000502:physiology*; D011942:Receptors, Adrenergic, alpha / Q000378:metabolism; D011943:Receptors, Adrenergic, beta / Q000378:metabolism; D013563:Sympathectomy, Chemical; D044024:Tetralones
D000317:Adrenergic alpha-Antagonists; D001679:Biogenic Amines; D009419:Nerve Tissue Proteins; D010627:Phenethylamines; D011941:Receptors, Adrenergic; D011942:Receptors, Adrenergic, alpha; D011943:Receptors, Adrenergic, beta; D044024:Tetralones; C010652:BE 2254; D010869:Pindolol; D009638:Norepinephrine