title: Characterization and possible role of growth factor and lymphokine receptors in the regulation of cholinergic function in the mammalian brain.
abstract: Using in vitro receptor autoradiographic techniques, we characterized the distribution of various growth factor (GF) and lymphokine receptors in the rat brain. In neonatal brain, specific insulin-like GF-1 (IGF-1) and epidermal GF (EGF) sites were observed in various regions. In particular, dense [125I]IGF-1 and [125I]EGF labelling was seen in the hippocampal formation. In the adult (3-month old) rat brain, a broader distribution of IGF-1 sites was apparent, whereas few EGF sites were visualized. As in the neonate, the adult hippocampus was enriched with IGF-1 binding sites. In addition, high levels of interleukin-2 (IL-2) binding sites were detected in the hippocampus of the adult rat. Exogenous IGF-1, EGF, and IL-2 significantly reduced the potassium (25 mM)-evoked release of acetylcholine (ACh) from slices of rat hippocampus. The GF effects were restricted to the adult hippocampus; neither IGF-1 nor EGF altered ACh release from slices of immature (6- and 18-day old) rat brain. Moreover, the GF and IL-2-mediated effects on ACh release appear to be specific to the hippocampus. For example, ACh release from frontal cortex or striatum was not significantly affected by either GFs or IL-2. In summary, our results suggest that in the rat hippocampus, IGF-1, EGF, and IL-2 may be important modulators of cholinergic activity.
authors.affiliation: Douglas Hospital Research Centre, McGill University, Montreal, Quebec, Canada.
authors.forename: D M
authors.initials: DM
authors.lastname: Araujo
authors.forename: P A
authors.initials: PA
authors.lastname: Lapchak
authors.forename: J G
authors.initials: JG
authors.lastname: Chabot
authors.forename: N P
authors.initials: NP
authors.lastname: Nair
authors.forename: R
authors.initials: R
authors.lastname: Quirion
mesh_terms: D000818:Animals; D004815:Epidermal Growth Factor / Q000378:metabolism* / Q000494:pharmacology; D006624:Hippocampus / Q000187:drug effects / Q000378:metabolism*; D007334:Insulin-Like Growth Factor I / Q000378:metabolism* / Q000494:pharmacology; D007376:Interleukin-2 / Q000378:metabolism* / Q000494:pharmacology; D051381:Rats; D011950:Receptors, Cholinergic / Q000187:drug effects* / Q000378:metabolism*; D013002:Somatomedins / Q000378:metabolism*
chemical_list: D007376:Interleukin-2; D011950:Receptors, Cholinergic; D013002:Somatomedins; D004815:Epidermal Growth Factor; D007334:Insulin-Like Growth Factor I