Beta-Adrenergic Binding Sites in Fetal Rat Central Nervous System and Pineal Gland: Their Relation to Other Receptor Sites

Abstract

Regional development of β-adrenergic binding sites in the rat fetal central nervous system and pineal gland were studied in relation to the ontogeny of different drug and neurotransmitter binding sites. 3H-dihydroalprenolol labels the olfactory bulb very early in fetal life. A comparatively early development of binding sites is also seen for benzodiazepines during late gestation. 3H-serotonin, 3H-muscimol, 3F1-GABA and 3H- (N)-methylscopolamine additionally label the olfactory bulb, revealing quite different patterns. Around gestational day 16, β-adrenergic sites were found in the neocortex, then in choroid plexus and in the pineal gland. Besides β-adrenergic, only 3H-flunitrazepam binding sites are detectable in the fetal eye, the latter with a more restricted regional distribution. In the fetal pineal, β-adrenergic, muscarinic cholinergic and serotonergic binding sites appear at different times in gestation. In the neocortex a variety of binding site patterns develop. Two more general types can be distinguished: appearance along with caudorostral maturation of the brain and appearance within distinct brain regions, possibly related to local differentiation processes. The simultaneous onset of various binding sites in distinct areas of the fetal brain might result in higher sensitivity of individual brain areas to drugs.

β2-Adrenergic receptor gene variants and risk for autism in the AGRE cohort

“…Neurotransmitters are thought to play a role as growth factors, with b-adrenergic agonists inhibiting proliferation while promoting differentiation. 2 Work with rodents shows that functional b-adrenergic receptors are expressed in the central nervous system during gestation, 3,4 and research on the effects of exposure to terbutaline, a b 2 -adrenergic receptor agonist, has produced evidence that pharmaceutical stimulation of the receptor in the fetus alters patterns of brain development [5][6][7][8] and could potentially increase risk for autism. 9 This suggests that other factors increasing stimulation of this receptor and the ensuing pathways, including functional polymorphisms in the receptor gene (ADRB2, also known as B2AR), may affect neurodevelopment and be associated with increased risk for autism.…”

Cholinergic signal transduction cascades in rat pinealocytes: functional and ontogenetic aspects

“…These [4,20]. The [27,28] to low levels in adulthood [8,19,35] [13]. More likely, activation of mAChRs may play a regulatory role in the development of the pineal gland, in general, and in the maturation of the melatonin-generating system, in particular.…”

Distribution and development of β‐adrenergic receptors in the rat olfactory bulb

“…Approximately one-third of the norepinephrine in the olfactory bulb is observed in the more superficial layers of the bulb (Nadi et al, 19801, and the highest concentration of norepinephrine in the bulb is found in the external plexiform layer (Jaffe and Cuello, 1980). Several studies have observed comparatively low densities of beta-adrenergic receptors (BARS) in the olfactory bulb of embryonic (Schlumpf et al, 1987) and adult mammals (Nadi et al, 1980;Palacios and Kuhar, 1982;Booze et al, 1989;Wanaka et al, 1989). None of these studies, however, have analyzed carefully the beta-adrenergic receptor density in the olfactory bulb postnatally with quantitative methods.…”