title: Functional assessment of toad parotoid macroglands: a study based on poison replacement after mechanical compression.
abstract: Toads have a pair of parotoid macroglands behind the eyes that secrete poison used in passive defence against predators. These macroglands are composed of juxtaposed alveoli, each one bearing a syncytial gland, all connected to the exterior by ducts. When the parotoids are bitten, the poison is expelled on the predator oral mucosa in the form of jets, causing several pharmacological actions. After poison release, the empty secretory syncytia immediately collapse in the interior of their respective alveoli and gradually start refilling. After parotoid manual compression, simulating a predator's bite, we studied, by means of morphological methods, the replacement of the poison inside the alveoli. The results showed that after compression, a considerable number of alveoli remained intact. In the alveoli that were effectively affected the recovery occurs in different levels, from total to punctual and often restrict to some areas of the syncytia. The severely affected alveoli seem not recover their original functional state. The fact that only a part of the parotoid alveoli is compressed during an attack seems to be crucial for toad survival, since the amphibian, after being bitten by a predator, do not lose all its poison stock, remaining protected in case of new attacks.
authors.affiliation: Laboratório de Biologia Celular, Instituto Butantan, São Paulo, Brazil.
authors.forename: Simone G S
authors.initials: SG
authors.lastname: Jared
authors.affiliation: Laboratório de Biologia Celular, Instituto Butantan, São Paulo, Brazil.
authors.forename: Carlos
authors.initials: C
authors.lastname: Jared
authors.affiliation: Departamento de Biologia Estrutural e Funcional, EPM, Universidade Federal de São Paulo, Brazil.
authors.forename: Mizue I
authors.initials: MI
authors.lastname: Egami
authors.affiliation: Laboratório de Biologia Celular, Instituto Butantan, São Paulo, Brazil.
authors.forename: Pedro L
authors.initials: PL
authors.lastname: Mailho-Fontana
authors.affiliation: Departamento de Zoologia, Instituto de Biociências, Universidade de São Paulo, Brazil.
authors.forename: Miguel T
authors.initials: MT
authors.lastname: Rodrigues
authors.affiliation: Laboratório de Biologia Celular, Instituto Butantan, São Paulo, Brazil. Electronic address: marta.antoniazzi@butantan.gov.br.
authors.forename: Marta M
authors.initials: MM
authors.lastname: Antoniazzi
mesh_terms: D000664:Amphibian Venoms / Q000378:metabolism*; D000818:Animals; D001938:Brazil; D002025:Bufonidae / Q000502:physiology*; D005088:Exocrine Glands / Q000033:anatomy & histology / Q000502:physiology*; D008297:Male; D010812:Physical Stimulation
chemical_list: D000664:Amphibian Venoms
keywords: Amphibia; Bufonidae; Parotoids; Poison; Skin glands; Toads