# Pharmacological evidence for the presence of inhibitory EP2 prostanoid receptors in the pregnant baboon myometrium

Rafael Garcia Villar, Lucy Green, Susan Jenkins, Richard A Wentworth, Peter W Nathanielsz

► To cite this version:

Rafael Garcia Villar, Lucy Green, Susan Jenkins, Richard A Wentworth, Peter W Nathanielsz. Pharmacological evidence for the presence of inhibitory EP2 prostanoid receptors in the pregnant baboon myometrium. 40th annual meeting of the Society for gynecologic Investigation, Mar 1993, Toronto, Ontario, Canada. p.19. hal-01606198

HAL Id: hal-01606198

https://hal.science/hal-01606198

Submitted on 7 Jun 2020

HAL is a multi-disciplinary open access
archive for the deposit and dissemination of sci-
entific research documents, whether they are pub-
lished or not. The documents may come from
teaching and research institutions in France or
abroad, or from public or private research centers.

L'archive ouverte pluridisciplinaire HAL, est
destinée au dépôt et à la diffusion de documents
scientifiques de niveau recherche, publiés ou non,
émanant des établissements d'enseignement et de
recherche français ou étrangers, des laboratoires
publics ou privés.

<figure><img src="image_1.png" /></figure>

Distributed under a Creative Commons Attribution - ShareAlike 4.0 International License
SOCIETY FOR GYNECOLOGIC INVESTIGATION

ABSTRACT FORM

Office Use Only:

ID# Abst# P.19

Date Rec'd March 31 - April 3 - 1993

40TH ANNUAL MEETING, TORONTO, CANADA

DO NOT FOLD ABSTRACT FORM

PHARMACOLOGICAL EVIDENCE FOR THE PRESENCE OF INHIBITORY EP2 PROSTANOID RECEPTORS IN THE PREGNANT BABOON MYOMETRIUM. Rafael Garcia Villar*, Lucy Green*, Susan Jenkins*, Richard A. Wentworth*, and Peter W. Nathanielsz. Laboratory for Pregnancy and Newborn Research, Dept. Physiology, College of Veterinary Medicine, Cornell University, Ithaca New York 14853. Supported by HD 21350.

Endogenous prostanoids (mainly PGE₂) have been shown to be either inhibitory or stimulatory to myometrial contractions in the pregnant primate : the nature of the myometrial response to PGE2 depending on the interaction with specific receptors, namely EP prostanoid receptors, divided into putatively inhibitory (EP2) and activatory (EP1 and EP3) subtypes (1). The present in vitro study was conducted to determine whether EP2 prostanoid receptors could be pharmacologically demonstrated on the myometrium of the pregnant baboon in the last third of pregnancy.

**METHODS:** Myometrium (2 x 4 cm piece) was removed from the body of the uterus of four pregnant baboons at 160-183 days gestation (term 175 - 185 days) under halothane general anesthesia. Muscle strips (0.4 x 1 cm) were suspended in an 8-chamber in vitro superfusion system (2) in the direction of the longitudinal fibers. A cumulative concentration-response curve to oxytocin (OT) was obtained over the range 10⁻¹² to 10⁻⁶ M. A concentration of OT close to the EC₅₀ was chosen, the myometrial contractility was driven at this dose, and a concentration-response curve to the putative EP2 prostanoid receptor agonist AH13205 (Glaxo, UK; range 10⁻¹⁰ to 10⁻⁵ M) was constructed.

**RESULTS:** OT dose-dependently enhanced the activity level of myometrial muscle strips with a calculated EC₅₀ in the nanomolar range (2.5 ± 2.1 nM, n=10 experiments). In three of four baboons (Fig. 1), AH13205 dose-dependently inhibited the amplitude and the frequency of OT (4.2 10⁻⁹ M) driven myometrial contractions (Fig. 1).

**CONCLUSION:** The response of the myometrium to various prostanoids produced in late gestation and at parturition will depend on the factors that regulate the expression of specific prostanoid receptor subtypes. Our study suggests that the inhibitory EP2 receptor-subtype is present in the pregnant baboon myometrium during the last third of gestation, where it probably contributes to maintaining a low level of myometrial contractility.

**REFERENCES:** 1 Senior J, Marshall K, Sangha R et al (1991). Br J Pharmacol 102, 747-753; 2 Coleman RA, Nials AT (1989). J Pharmacol Met 21, 71-86.

<figure><img src="image_2.png" /><figcaption>Fig. 1 OT concentration-response curve (A) and AH 13205 induced inhibition (B) of myometrial activity from two baboons near term.</figcaption></figure>

ABSTRACT MUST BE RECEIVED BY CLOSE OF BUSINESS (5:00 PM), FRIDAY, OCT. 2, 1992.

**Mail to:**

Ms. Laurie Daniels
Dept. of Ob-Gyn
The Univ. of Texas
Southwestern Med. Ctr.
5323 Harry Hines Blvd.
Dallas, TX 75235-9032

Select the section that should review this abstract (check one)

<figure><img src="image_3.png" /></figure>

Basic Endocrinology
Clinical Endocrinology
Basic Perinatology
Clinical Perinatology
Genetics
Immunology
Oncology
Infections

<figure><img src="image_4.png" /></figure>

Contraception
Epidemiology
Gynecology
Other

**Presentation Preference:**

<figure><img src="image_5.png" /></figure>

Slide Presentation

<figure><img src="image_6.png" /></figure>

Poster Presentation

<figure><img src="image_7.png" /></figure>

No Preference,
Slide vs. Poster

Withdrawal may be made only for sufficient cause in writing.

**Session Preferred:**

Code Number/Category

149-Prostaglandins

260-Uterine/
Contractility

343-Parturition

☐ Check here if the first author is a research fellow funded by Institution such as NIH, AGOS, ACOG, etc.

Name of sponsoring organization

**IMPORTANT:** Be sure to stay within border. See sample abstracts, typing, and mailing instructions on the reverse side of this form. Use enclosed check list for abstract preparation. The original typed copy of this abstract form (for reproduction by photo-offset in the 1993 Annual Program of the Society for Gynecologic Investigation) must be submitted, together with two photocopies of the abstract form and ten (10) additional double-spaced copies on plain 8 1/2" X 11" paper. For additional copies, include title, but omit name(s) of author(s) and identifying institution(s). All material must reach Laurie Daniels NO LATER THAN THE CLOSE OF BUSINESS (5:00 P.M.), FRIDAY, OCTOBER 2, 1992. Use air mail or express mail from overseas.

**Mailing address of first author** (Please print or type)

Rafael Garcia Villar
Lab. Pregnancy and Newborn Research
Dept. Physiology
College of Vet. Med.
Cornell University
Ithaca, NY 14853

(607) 253-3082

Telephone No.

Each abstract form submitted MUST BE SIGNED by a member of The Society for Gynecologic Investigation. As a member of the SGI, I assume full responsibility for the quality of this material and its presentation, if selected. I also assume the $30 penalty fee for retyping and/or corrections as charged by the Program Committee. **In addition, this material will not be published, or presented at a national meeting, prior to its presentation at the SGI, if accepted.**

(Member's Name) Peter W. Nathanielsz, M.D., Ph.D.

(Member's Signature) John W. Nathanielsz

<figure><img src="image_8.png" /></figure>

(Member's Phone No.) (607) 253-3082