Uterine blood flow, myometrial activity and their response to adenosine during the peri-implantation period in sheep
in ReproductionSearch for other papers by I. R. Fleet in
Current site
Google Scholar
PubMed
Search for other papers by R. B. Heap in
Current site
Google Scholar
PubMed
Summary. Uterine blood flow and myometrial activity were measured simultaneously in anaesthetized sheep 15 days after a sterile (non-pregnant group) or fertile (pregnant) mating. During the peri-implantation period uterine blood flow was similar in both groups of animals, but spontaneous myometrial activity was greatly reduced in pregnant ewes. This 'block' of myometrial activity was associated with circulating levels of progesterone which were significantly higher (2·8 ± 0·8 ng/ml, mean ± s.e.m.) than those in non-pregnant animals (0·4 ± 0·3 ng/ml). Adenosine injected into the uterine artery produced uterine vasodilatation in both groups, but the log dose–response was significantly less in pregnant than in non-pregnant animals (P < 0·001). Myometrial activity was stimulated by adenosine, particularly in the pregnant group (P < 0·001). Vascular and myometrial effects were potentiated by a previous infusion of dipyridamole. Occlusion of the uterine artery produced reactive hyperaemia, and oestradiol infused close-arterially induced vasodilatation after a lag phase of about 30 min. Our results are consistent with a hypothesis that vascular and myometrial cells in the uterus may contain two types of adenosine receptor, one mediating excitatory and the other inhibitory responses, and that both responses are modified by the presence of a conceptus. The results also support the idea that oestrogens produce uterine vasodilatation by increasing the local concentration of vasoactive substances.
Reproduction is committed to supporting researchers in demonstrating the impact of their articles published in the journal.
The two types of article metrics we measure are (i) more traditional full-text views and pdf downloads, and (ii) Altmetric data, which shows the wider impact of articles in a range of non-traditional sources, such as social media.
More information is on the Reasons to publish page.
| Sept 2018 onwards | Past Year | Past 30 Days | |
|---|---|---|---|
| Full Text Views | 202 | 82 | 44 |
| PDF Downloads | 140 | 30 | 3 |
Online ISSN: 1741-7899
Print ISSN: 1470-1626
Strengthening biomedical communities
to advance science and health
CONTACT US
Bioscientifica Ltd | Starling House | 1600 Bristol Parkway North | Bristol BS34 8YU | UK
Bioscientifica Ltd | Registered in England no 3190519