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Timing of parturition in two species of viviparous lizard: influences of b-adrenergic stimulation and temperature upon uterine responses to arginine vasotocin (AVT)

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Atkins, N and Jones, SM and Guillette, LJ (2006) Timing of parturition in two species of viviparous lizard: influences of b-adrenergic stimulation and temperature upon uterine responses to arginine vasotocin (AVT). Journal of Comparative Physiology B: biochemical, systemic, and environmental physiology, 176 (8). pp. 783-792. ISSN 1096-4959

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Abstract

The southern snow skink Niveoscincus microlepidotus
is a viviparous alpine lizard with biennial
reproduction, in which embryos are fully developed
before winter but parturition is delayed until spring.
We aimed to determine whether, in this species, in
vitro uterine preparations are responsive to arginine
vasotocin (AVT) and prostaglandin (PGF2a) in autumn
and spring, and whether pre-treatment with the
b-adrenergic agonist isoproterenol decreases the
effectiveness of AVT in stimulating uterine contractions.
Using the spotted snow skink (Niveoscincus
ocellatus), an annually breeding species, we aimed to
determine influences of temperature and the b-adrenergic
system upon the response to AVT in vivo. In both
N. microlepidotus and N. ocellatus females are more
responsive to AVT than to PGF2a, and that the response
to AVT is decreased, but not prevented, by badrenergic
stimulation. In N. microlepidotus, uteri are
equally responsive in both seasons to the hormones
administered. In N. ocellatus environmental conditions,
specifically, temperature, modulate the response to
AVT in vivo with the time to parturition increasing as
temperature decreases. We conclude that in these
viviparous squamates the endocrine cascade leading to
parturition is modulated by the b-adrenergic system,
and that this may reflect the mechanism by which the
timing of parturition is tied to suitable environmental
conditions.

Item Type: Article
Keywords: Environment Niveoscincus Oviduct Prostaglandin F2a
Journal or Publication Title: Journal of Comparative Physiology B: biochemical, systemic, and environmental physiology
Page Range: pp. 783-792
ISSN: 1096-4959
Identification Number - DOI: 10.1007/s00360-006-0100-0
Additional Information:

The original publication is available at www.springerlink.com

Date Deposited: 21 Jul 2008 04:23
Last Modified: 18 Nov 2014 03:46
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