Article

Reproductive cycle of the Neotropical Crotalus durissus terrificus: II. Establishment and maintenance of the uterine muscular twisting, a strategy for long-term sperm storage

Laboratório de Farmacologia, Instituto Butantan, Av. Dr. Vital Brazil 1500, Butantã 05503-900, São Paulo, SP, Brazil; Laboratório de Herpetologia, Instituto Butantan, Av. Dr. Vital Brazil 1500, Butantã 05503-900, São Paulo, SP, Brazil
General and Comparative Endocrinology DOI:10.1016/j.ygcen.2004.09.002 pp.151-157

ABSTRACT Crotaline snakes store sperm by means of a uterine musculature twisting (UMT). We investigated the influence of plasma levels of estradiol and progesterone and vasotocinase cystine aminopeptidase (CAP) activity on UMT formation and maintenance, and the in vitro uterine reactivity for AVT in Crotalus durissus terrificus in primary or secondary vitellogenesis with or without UMT. Frequency of females in secondary vitellogenesis with UMT is significantly higher than in primary one. Estradiol levels did not vary in all conditions studied, however, significantly low levels of progesterone were found in snakes in secondary vitellogenesis with UMT compared to those without it. UMT is always observed when high levels of estradiol and low levels of progesterone are detected. CAP activity did not change in the presence of UMT. AVT produced concentration–response contractions of the isolated uterus of snakes in all stages analysed and the pD2 value and maximum contractile response were significantly higher in primary vitellogenesis without UMT than in other reproductive conditions, indicating that uterus of those snakes presents a higher contractile capacity which may favour UMT establishment. In conclusion, we show a relationship of UMT and estradiol/progesterone balance and a possible participation of AVT in UMT formation and maintenance in the Neotropical rattlesnake.

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Keywords

CAP activity
 
concentration–response contractions
 
Crotaline snakes store sperm
 
Crotalus durissus terrificus
 
estradiol/progesterone balance
 
higher contractile capacity
 
isolated uterus
 
maximum contractile response
 
Neotropical rattlesnake
 
pD2 value
 
possible participation
 
primary vitellogenesis
 
reproductive conditions
 
secondary vitellogenesis
 
snakes presents
 
stages analysed
 
UMT formation
 
uterine musculature twisting
 
vasotocinase cystine aminopeptidase
 
vitro uterine reactivity