PubMed · 3702971
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M Hitt, D D Ettinger. 1986-06-05. Toad toxicity.. https://pubmed.ncbi.nlm.nih.gov/3702971/
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The parotid glands of toads are constituted by an accumulation of venom-producing granular alveoli. Parotid glands of Bufo ictericus were manually compressed and immediately excised. Normal glands (not submitted to compression) were also excised and processed for histological and ultrastructural observations. The glandular body of large granular alveoli in parotid glands is formed by a myoepithelial layer, internally covered by a syncytial secretory layer. In the normal parotid gland this layer is very electron dense, thus preventing clear visualization of organelles. Large secretion granules are located in the main secretion mass, near the syncytium. In the compressed parotid gland, the myoepithelium shows a number of alterations, including presence of myelin figures and foci of degradation in the cytoplasm. The organelles of the syncytial cytoplasm are easily observed. The mitochondria are swollen; the cristae are shortened or absent. Syncytial secretion granules and lengthened structures linked to the syncytial matrix are to be seen. A large amount of smooth endoplasmic reticulum is present, while the rough endoplasmic reticulum is reduced. This large quantity of smooth endoplasmic reticulum suggests enhanced synthesis of the cardiotoxic steroids of the venom. Alterations in the mitochondria and the presence of myelin figures and degenerative foci in the cytoplasm may probably be regarded as consequences of the cellular injury provoked by compression.
The behavioural and electrocortical (ECoG) effects induced by a methanol extract of the skin of the Australian frog Pseudophryne coriacea, directly microinjected into several areas of the brain, were studied in freely moving rats. Administration of the P. coriacea extract (5, 10, 15 and 20 micrograms) into the dorsal hippocampus produced a dose-dependent and reversible behavioural stimulation and ECoG spikes lasting 20-140 min. Similar but less intense effects were elicited in rats receiving injections into the III cerebral ventricle, amygdala and caudate nucleus. In conclusion, the present experiments show that the skin extract of P. coriacea produces behavioural stimulation and ECoG spikes when injected into the rat brain, the most sensitive area being the hippocampus.
The effects of Bombina variegata cutaneous venom (Bvv) on eukaryotic cell growth has been assessed employing the human leukaemic cell line HL 60, by liquid and agar semisolid cultures and 51Cr release assay. HL 60 cells growth is impaired by Bvv in a dose-dependent fashion in both culture systems. The arrest of proliferation requires a contact time lower than 3 min and it is not reversed by washing and culturing the cells in a Bvv-free medium. Similarly, an extremely short exposure time is needed to determine maximum 51Cr release. Neither the agar medium nor the fetal calf serum interact with Bvv effects, which, according to the above findings, must be regarded as cytolytic in nature. In both liquid and the agar-semisolid culture Bvv cytolytic activity half life is about 8 hr. The cytolytic properties of Bvv are thought to be part of the chemical defence system of amphibian skin.