Collection of Toad Venoms and Chemistry of the Toad Venom Steroids

Meyer, Kuno; Linde, Horst H. A.

doi:10.1016/b978-0-12-138902-4.50027-1

Cited by 54 publications

(31 citation statements)

References 102 publications

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“…This conclusion is based on the following observations : (a) The mass spectrum of fractions VI and I1 corresponds to the suggested dienolide structures (Fig. 4); (b) The maximum ultraviolet absorbance of the material in fraction VI was 298 nm, an ultraviolet maximum characteristic of the dienolide system [25] ; (c) the digitalislike activity characteristic of steroids as delineated above. Our findings imply that the synthesis of six-membered cyclic unsaturated lactone steroids is not restricted to amphibian but is achieved by mammalian tissues as well.…”

Section: Discussionmentioning

confidence: 99%

Identification of digitalis‐like compounds in human cataractous lenses

Lichtstein¹,

Gati²,

Samuelov³

et al. 1993

European Journal of Biochemistry

135

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Human cataractous lens nuclei extract inhibited, in a dose-dependent fashion, [3H]ouabain binding to rat brain synaptosomes and microsomal Na+-and K+-dependent adenosine triphosphate (Na+ , K+-ATPase) activity and interacted with anti-digoxin antibodies. The compounds responsible for these activities, termed digitalis-like compounds (DLC), were also detected in bovine, rat, cat and rabbit, normal, transparent lenses, but the levels were only 0.7-5.4% of the average levels in the cataractous human lenses. DLC from the human cataractous lenses were purified by a procedure consisting of organic extractions and batch chromatography followed by filtration through a 3000 Da cut-off filter and subsequent separations using reverse-phase high-performance liquid chromatography. The presence of DLC in the different fractions obtained in the chromatograms was monitored by their ability to inhibit [3H]ouabain binding and Na+, K+-ATPase activity. Based on chemical ionization mass spectrometry together with ultraviolet spectrometry and biological characterization, it is suggested that new bufodienolides, 19-norbufalin and 19-norbufalin peptide derivatives are responsible for the endogenous DLC activity. It is proposed that these compounds may regulate Na+, K+-ATPase activity in the lens under some physiological and pathological conditions.The Na+-and K+-dependent adenosine triphosphate (Na+, K'-ATPase) is an integral plasma membrane protein responsible for the maintenance of Na+ and K' concentration gradients in all eukaryotic cells. Since Na+, K'-ATPase has a high-affinity receptor for digitalis steroids, it has been postulated that there are endogenous ligands for these receptors which regulate the Na+, K' pump activity. Indeed, based on their ability to inhibit ['Hlouabain binding and Na+, K+-ATPase activity, digitalis-like compounds (DLC) have been shown to be present in the brain [l-31, heart [4] [24]. However, none of these compounds appears to be the natural ligand of the digitalis receptor of the Na+, K+-ATPase because of their limited specificity and affinity. Bufodienolides, which resemble the structure of the plant cardiac glycosides, have been identified in the plasma, brain and other tissues of toads [14, 15, 25, 261, however, their

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Section: Discussionmentioning

confidence: 99%

Identification of digitalis‐like compounds in human cataractous lenses

Lichtstein¹,

Gati²,

Samuelov³

et al. 1993

European Journal of Biochemistry

135

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“…Improved pharmacological approaches would therefore furnish researchers with suitable methods for obtaining pure serous secretions from skins with several gland types. Routine techniques of poison collection, which usually involve mechanical compression of living specimens (Meyer and Linde 1971) are not specific since the material spread over the body surface includes both poison products and mucus. As an alternative method, ether stimulation triggers systemic reactions, and requires preliminary manoeuvres of the animals to deplete the urinary bladder and avoid contamination by urine (Kiss and Michl 1962).…”

Section: Discussionmentioning

confidence: 99%

Serous gland polymorphism in the skin of Phyllomedusa hypochondrialis azurea (Anura, Hylidae): response by different gland types to norepinephrine stimulation

et al. 2002

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Stimulation by norepinephrine in physiological concentration was used on the dorsal skin of the Argentine tree-frog Phyllomedusa hypochondrialis azurea to trigger contraction of myoepithelial cells encircling the serous glands and provoke secretory release. This hylid species possesses two kinds of serous cutaneous glands, producing secretory granules or vesicles (type Ia and Ib serous units, respectively), along with serous-derived glands which synthesise lipids and store them in complex aggregates (type II units). Structural and ultrastructural observations on myoepithelia, secretory units and gland products collected in saline after discharge, revealed consistent but different responses in the three types investigated. Type Ia glands reacted intensely to treatment, with both contractile and secretory responses, type Ib glands were only mildly affected in their myoepithelia and glands of type II were not affected at all. According to data available in the literature, these findings suggest that: (a) the dense (type Ia) granules are expelled as a phasic response through bulk (holocrine) discharge, (b) the secretory (type Ib) vesicles are released as a tonic response through a merocrine mechanism and (c) lipid (type II) aggregates are exuded as a secretory component of a complex behavioural response which tends to reduce transcutaneous water loss. Furthermore, these findings indicate that the use of pharmacological modulation of myoepithelial activity allows selective collection of skin products in species characterised by serous gland polymorphism.

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“…were collected from the vicinity of Kakatiya University hostel buildings, Warangal, A.P., India. The parotoid glands were gently pressed with the help of sterile forceps to release the secretions according to Meyer and Linde (1971) [13] and these secretions were collected into ice-jacketed containers. The secretions were weighed to nearest milligram.…”

Section: Studies On Heart Beatmentioning

confidence: 99%