The effect of catecholamines and their antagonists on the fertilization of cumulus‐free mouse ova in vitro at a suboptimal spermatozoal density

Abstract

A suboptimal sperm concentration was used to assess the capacity of catecholamines to stimulate the fertilization of cumulus free F1,(C57BL × CBA) mouse ova in vitro. At a concentration of 50 μM, (L) epinephrine significantly increased the proportion of ova fertilized at 2 × l05 spermatozoa/ml. However, when (D, L) propranolol at an equimolar concentration was tested for inhibition of the (L) epinephrine effect, fertilization was inhibited in both the test and control dishes. At l0μM, propanolol by itself or in the presence of 50μM (L) epinephrine significantly increased the number of ova fertilized at 2 × l05 sperm/ml. Norepinephrine (50 μM) and phentolamine (50 μM), either alone or together, were also slightly stimulatory. Some data are presented to suggest that propranolol may act in a nonadrenergic manner to precipitate the acrosome reaction and that the stimulatory effect is maximised when it is added to spermatozoa at the same time as ova addition. It was suggested that propranolol may act to trigger calcium influx by a nonspecific alteration in membrane function for example in (Ca + Mg) ATPase activity. It was concluded that spermatozoa at suboptimal densities are capable of achieving fertilization and that sperm concentration dependency in fertilization in vitro may be a reflection of the proportion of spermatozoa achieving capacitation.

Molecules that initiate or help stimulate the acrosome reaction by their interaction with the mammalian sperm surface

“…The stimulation appears to be receptor-mediated since several receptor antagonists inhibited stimulation of the AR and fertilization. There are no published studies suggesting receptormediated stimulation of the AR by biogenic amines in other species, but Stanger (1983) has reported that catecholamines stimulate in vitro mouse fertilization, although antagonists also stimulated it (see Meizel et al, 1984 for discussion). Meizel and Turner (1983a) reported that serotonin (50 p M ) or its agonist 5-methoxytryptamine (5 pM), but not the catecholamines (50 pM) epinephrine, norepinephrine, or dopamine, could stimulate the hamster AR 15 min after addition at 4.5 hr of capacitation.…”

Animal in Vitro Fertilization and Embryo Development

“…Quite possibly, HSA contains epinephrine or some other biogenic amine (Meizel ef al., 1984) perhaps in larger amounts than BSA, in view of its greater efficiency in capacitating spermatozoa. Epinephrine has recently been shown to significantly enhance the fertilizing ability of mouse spermatozoa in vitro when they were incubated at suboptimal concentrations (Stanger, 1983). The mechanism of action of epinephrine (and of other biogenic amines) in stimulating sperm-fertilizing ability is unknown.…”

Capacitation and Induction of the Acrosome Reaction in Bull Spermatozoa With Norepinephrine

“…Several studies have suggested a role for catecholamines in capacitation of spermatozoa (Bavister et al, 1976;Leibfried and Bavister, 1982;Stanger, 1983;Bize and Santander, 1985). Hamster epididymal spermatozoa incubated with epinephrine and taurine for 3.5 hours were capable of acrosome reacting following exposure to LPC (Llanos and Ronco, 1994).…”