title: Mast cell population in the frog brain: distribution and influence of thyroid status.
abstract: In the developing frog brain, the majority of mast cells (MC) are distributed in the pia mater, and some immature MC are located adjacent to the blood capillaries in and around the neuropil. In the adult brain, MC are more numerous than in pre- and pro-metamorphic tadpoles; they are mainly located within the pia mater and are particularly numerous in the choroid plexuses. Many MC are found within the brain ventricles juxtaposed to the ependymal lining. MC are rarely observed in the brain parenchyma. In the adult brain, MC number is much higher than in the brain of post-metamorphic froglets. In the latter, MC number is nearly 2-fold over that found in the pre-metamorphic brain. Treatment of pre- and pro-metamorphic tadpoles with 3,5,3'-triiodothyronine (T(3)) and thyroxine (T(4)) stimulates overall larval development but does not induce a significant change in MC population within the brain. By contrast, treatment with 6-n-propyl-2-thiouracil (PTU) delays larval development and leads to a significant numerical increase of brain MC. In the adult, PTU treatment also has a similar effect whereas hypophysectomy causes a drastic decrease of MC population. The negative effects of hypophysectomy are successfully counteracted by a two-week replacement therapy with homologous pars distalis homogenate. In the adult frog, MC population seems to be refractory to thyroid hormone treatment. The present study on frog brain suggests that pituitary-thyroid axis may be involved in the regulation of MC frequency.
authors.affiliation: Department of Life Sciences, Second University of Naples, Via Vivaldi, 43, 81100 Caserta, Italy.
authors.forename: Rossella
authors.initials: R
authors.lastname: Monteforte
authors.forename: Claudia
authors.initials: C
authors.lastname: Pinelli
authors.forename: Alessandra
authors.initials: A
authors.lastname: Santillo
authors.forename: Rakesh K
authors.initials: RK
authors.lastname: Rastogi
authors.forename: Gianluca
authors.initials: G
authors.lastname: Polese
authors.forename: Gabriella Chieffi
authors.initials: GC
authors.lastname: Baccari
mesh_terms: D000375:Aging / Q000187:drug effects; D000818:Animals; D001001:Anura / Q000254:growth & development / Q000378:metabolism*; D001921:Brain / Q000033:anatomy & histology / Q000166:cytology* / Q000187:drug effects / Q000254:growth & development; D020249:Hormone Replacement Therapy; D007016:Hypophysectomy; D008407:Mast Cells / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D008675:Metamorphosis, Biological / Q000187:drug effects; D016612:Paraffin Embedding; D010903:Pituitary Gland, Anterior / Q000187:drug effects; D013889:Thiouracil / Q000494:pharmacology; D013961:Thyroid Gland / Q000378:metabolism*; D013974:Thyroxine / Q000494:pharmacology; D014020:Tissue Extracts; D014284:Triiodothyronine / Q000494:pharmacology
chemical_list: D014020:Tissue Extracts; D014284:Triiodothyronine; D013889:Thiouracil; D013974:Thyroxine