Boyle Van't Hoff Plot
Abbildung 1: Boyle Van’t Hoff Plot of boar spermatozoa (Drawn on the basis of data presented in [22]). Data are presented in volume equivalents for ejaculated (unbroken line) and epididymal (broken line) boar spermatozoa at 39°C as measured by electronic cell counter. Boar spermatozoa behave as "perfect osmometers" in the range between 150–900 mOsmol/kg. The changes in aniso-osmotic volume V are given by the regression equation where x is the reciprocal of relative osmolality: • for epididymal spermatozoa, V = 8.2• x +16.2 where x = 1/300 mOsmol/kg R2 = 0.94 • for ejaculated spermatozoa, V = 8.5• x +15.1 where x = 1/300 mOsmol/kg R2 = 0.99 The osmotically inactive fraction of cell volume corresponds to 0.645•Viso in epididymal spermatozoa and to 0.626•Viso in ejaculated spermatozoa.


Keywords: Boyle Van't Hoff Plot,  Diagramm,  flowchart

Volume regulation
Abbildung 2: Mechanisms of volume regulation in mammalian spermatozoa (modified after [69]). A. Transport mechanisms involved. Swelling-activated potassium and chloride channels are involved in osmotically induced volume regulation in mammalian spermatozoa [68, 69]. Inhibition of chloride and potassium channels leads to restriction or loss of volume regulatory function. In contrast, inhibition of K+/Cl- co-transport or Na+/K+-ATPase has no negative effect on osmotically induced volume regulation though these systems may be involved in isoosmotic volume regulation, together with other mechanisms related to sodium, potassium, chloride and osmolyte transport. NPPB: 5-nitro-2-(3-phenylpropylamino)benzoic acid; DIDS: 4,4’-diisothiocyanatostilbene-2,2’-disulfonic acid. (These and tamoxifen are all inhibitors of chloride channels.) B. Putative modulation and signalling pathways of volume control. The activation, regulation or deactivation of transport mechanisms can be mediated by modulation of F-actin and cytoskeletal integrity and/or by changes in phosphorylation/dephosphorylation balance (activity of protein kinases and phosphatases). Depolymerisation of F-actin facilitates volume regulation; phosphorylation appears to be involved in the closing or deactivation of channels involved in volume regulation while dephosphorylation leads to activation of ion transport mechanisms (probably chloride channels [68, 69]). Red arrows and lines: negative (inhibiting) action on transport and signalling mechanisms; green arrows and lines: positive (accelerating) action.


Keywords: Schema,  scheme,  spermatozoa,  Spermatozoen,  volume regulation,  Volumenregulation