The combined use of isolated strips of guinea-pig lung parenchyma and ileum as a sensitive and selective bioassay for leukotriene B4

The effects of three calcium antagonists, verapamil, lanthanum, and 8-(N,N-diethylamino)octyl-3,4,5-trimethoxybenzoate (TMB-8) were studied on the release of slow-reacting substance of anaphylaxis (SRS-A) from ovalbumin-sensitized chopped guinea pig lung parenchyma in calcium-containing and calcium-free media. The SRS-A levels (mean ± SEM) obtained from tissues incubated in normal and calcium-free Krebs–bicarbonate buffer were 51 ± 8 (N = 19) and 21 ± 4 (N = 14) U/mL, respectively. TMB-8 (0.1–10 μM) a reported intracellular calcium antagonist, reduced antigen-stimulated SRS-A release from lung tissue incubated in calcium-containing, but not calcium-free, medium; A23187-induced SRS-A release from normal guinea pig lung was not significantly altered by TMB-8 at concentrations up to 10 μM. Verapamil and lanthanum consistently reduced SRS-A release only at high concentrations (100 μM and 1 mM, respectively). The quantities of SRS-A released from lung tissue incubated in the presence of verapamil in normal medium were similar to those obtained in calcium-free medium. Tissues incubated in the presence of potassium chloride (60 and 100 mM) did not release significant quantities of SRS-A, and release which did occur was not blocked by verapamil, suggesting that antigen-induced SRS-A release is not dependent on membrane depolarization and that verapamil was not exerting inhibition via blockade of voltage-dependent calcium channels. These data suggest that although intracellular calcium is important for the regulation of SRS-A secretion from guinea pig lung tissue, extracellular calcium is necessary for optimal release of SRS-A.

Download Full-text

Effects of vasoactive intestinal peptide, helodermin and galanin on responses of guinea-pig lung parenchyma to histamine, acetylcholine and leukotriene D4

British Journal of Pharmacology ◽

10.1111/j.1476-5381.1991.tb12542.x ◽

1991 ◽

Vol 104 (4) ◽

pp. 1012-1018 ◽

Cited By ~ 5

Author(s):

Dolores M. Conroy ◽

Marwa N. Samhoun ◽

Priscilla J. Piper

Keyword(s):

Guinea Pig ◽

Vasoactive Intestinal Peptide ◽

Lung Parenchyma ◽

Leukotriene D4

Download Full-text

Identification of a novel type 2 fiber population in mammalian skeletal muscle by combined use of histochemical myosin ATPase and anti-myosin monoclonal antibodies.

Journal of Histochemistry & Cytochemistry ◽

10.1177/38.2.2137154 ◽

1990 ◽

Vol 38 (2) ◽

pp. 257-265 ◽

Cited By ~ 184

Author(s):

L Gorza

Keyword(s):

Monoclonal Antibodies ◽

Guinea Pig ◽

Atpase Activity ◽

High Activity ◽

Skeletal Muscles ◽

Enzyme Histochemistry ◽

Myosin Atpase ◽

Myosin Atpase Activity ◽

Combined Use

A novel type of myosin heavy chain (MHC), called 2X, has been recently identified in type 2 fibers of rat skeletal muscles using an immunochemical approach. In the present study, the same panel of anti-MHC monoclonal antibodies was used in immunohistochemistry combined with enzyme histochemistry to identify and compare type 2X fibers in hindlimb skeletal muscles of rat, mouse, and guinea pig. Immunohistochemistry shows that 2X MHC is localized in a large subset of type 2 fibers and is co-expressed with 2A or 2B MHC in a small number of fibers. Enzyme histochemistry shows that type 2X fibers display low myosin ATPase activity after pre-incubation at pH 4.3 and high activity after paraformaldehyde pre-incubation at pH 10.4. After pre-incubation at pH 4.6, myosin ATPase shows intermediate and high activity in rat and mouse 2X fibers, respectively, whereas it is low in guinea pig 2X fibers. Succinate dehydrogenase displays moderate to high activity in 2X fibers of all species. Taken together, these staining patterns allow this novel fiber population to be distinguished from the other type 2 fibers using only enzyme histochemistry. Nevertheless, the combined use of immuno- and enzyme histochemistry prevents incorrect fiber typing due to the interspecies variability of myosin ATPase activity among the correspondent fiber types, and completely modifies the presently used classification of mouse type 2 fibers.

Download Full-text