Relationship between bicarbonate and cyclic nucleotide in the promoting effects on head-to-head agglutination in boar spermatozoa.
- Author:
Hiroshi HARAYAMA
1
;
Seishiro KATO
Author Information
- Publication Type:Journal Article
- MeSH: 1-Methyl-3-isobutylxanthine; pharmacology; Animals; Bucladesine; pharmacology; Cyclic AMP; physiology; Cyclic GMP; analogs & derivatives; pharmacology; physiology; Male; Papaverine; pharmacology; Purinergic P1 Receptor Antagonists; Sodium Bicarbonate; pharmacology; Sperm Agglutination; drug effects; physiology; Sperm Head; drug effects; physiology; Swine; Theophylline; analogs & derivatives; pharmacology
- From: Asian Journal of Andrology 2002;4(2):87-96
- CountryChina
- Language:English
-
Abstract:
AIMTo clarify the relationship between bicarbonate and cAMP in the promoting effects on the sperm agglutination.
METHODSSpermatozoa were collected from mature boars, washed and resuspended in a modified Krebs-Ringer HEPES lacking calcium chloride (mKRH). The sperm suspensions were incubated in a water bath (38.5 degrees C) for 60 min and then the percentage of head-to-head agglutinated spermatozoa was determined.
RESULTSSupplementation of the mKRH with sodium bicarbonate (5-10 mM) significantly raised the percentage of head-to-head agglutinated spermatozoa in the samples. The addition of selective inhibitors for calcium/calmodulin-dependent phosphodiesterases (type 1: 8-methoxymethyl-IBMX and vinpocetine, 25-50 micro M) or for cAMP-specific phosphodiesterases (type 4: Ro20-1724 and rolipram, 25-50 microM) enhanced the effect of bicarbonate on sperm agglutination as highly as did the addition of non-selective inhibitors for phosphodiesterases (IBMX and papaverine, 25-50 microM). A calmodulin antagonist (W-7, 2 microM), that potentially blocks the stimulator of the calcium/calmodulin-dependent phosphodiesterases, significantly enhanced the effect of bicarbonate on sperm agglutination. Moreover, a phosphodiesterase-resistant cAMP analogue (cBiMPS, 0.1 mM) markedly induced agglutination in more spermatozoa (76%) after the incubation without bicarbonate and phosphodiesterase inhibitors than did a less potent cAMP analogue (dibutyryl cAMP, 1 mM) (21%), while three kinds of cGMP analogues (0.1-1 mM) had no effect on sperm agglutination. In addition, a cAMP antagonist (Rp-cAMPS, 1 mM) significantly reduced the sperm agglutination resulting from the actions of bicarbonate and IBMX. On the other hand, the effect of bicarbonate was abolished by a change of incubation temperature from 38.5 degrees C to 25 degrees C.
CONCLUSIONThese findings demonstrate that the bicarbonate-induced agglutination of boar spermatozoa is controlled via the cAMP-mediated, temperature-dependent signaling cascade. This cascade is suppressed by the action of the phosphodiesterase (at least types 1 and 4).
