title: Head-to-head association in bovine spermatozoa induced by catecholamines.
abstract: Noradrenaline, adrenaline, and isoproterenol induce head-to-head association in bovine spermatozoa in a Tris-HCl-buffered medium. Noradrenaline was the most and isoproterenol the least efficient. This effect was stimulated by Ca2+, Mg2+ and Mn2+, Ca2+ being more efficient than the other two ions. At 2 X 10(-6) M Ca2+, oxidation products of adrenaline dissociated spermatozoa associated by washing; at 2 X 10(-5) M Ca2+, the dissociating effect was transformed into association. The induction of association by adrenaline was blocked by both alpha- and beta-adrenergic blockers at low concentrations (2 X 10(-7) M). Both cAMP and dibutyryl substituted cAMP (db-cAMP) induced association in the Tris-buffered medium at 2 X 10(-6) M Ca2+. Further increase in association was brought about by increasing the Ca2+ concentration to 2 X 10(-5) M. Prolongation of the treatment with cAMP increased association. When combined with cAMP under the same conditions as used in the combination with adrenaline, L-propranolol did not inhibit association induced by cAMP. In an identical experiment, performed in Tyrode solution, L-propranolol inhibited association induced by cAMP. At 2 X 10(-5) M, theophylline, caffeine, and papaverine induced association in the presence of 2 X 10(-5) M Ca2+. The results are compatible with the hypothesis that catecholamines act via receptors and formation of cAMP.
mesh_terms: D015105:3',5'-Cyclic-AMP Phosphodiesterases / Q000037:antagonists & inhibitors; D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology; D000319:Adrenergic beta-Antagonists / Q000494:pharmacology; D000323:Adrenochrome / Q000502:physiology; D000818:Animals; D003994:Bucladesine / Q000494:pharmacology; D002118:Calcium / Q000502:physiology; D002395:Catecholamines / Q000502:physiology*; D002417:Cattle; D002449:Cell Aggregation / Q000187:drug effects; D000242:Cyclic AMP / Q000494:pharmacology; D008297:Male; D013077:Sperm Head / Q000187:drug effects / Q000502:physiology*; D013094:Spermatozoa / Q000502:physiology*
chemical_list: D000317:Adrenergic alpha-Antagonists; D000319:Adrenergic beta-Antagonists; D002395:Catecholamines; D003994:Bucladesine; D000323:Adrenochrome; D000242:Cyclic AMP; D015105:3',5'-Cyclic-AMP Phosphodiesterases; D002118:Calcium