IP Injection of Phenylephrine and Prazocin on Tonic Pain during Estrus Cycle in Rats

• Published in: Journal of Applied Animal Research Vol. 25; no. 1; pp. 53 - 55
• Main Authors: Taherianfard, M., Bahaoddini, A., Rajaian, H., Dabbaghlotfi, A.
• Format: Journal Article
• Language: English
• Published: Taylor & Francis Group 01.03.2004
• Subjects: estrus cycle; Phenylephrine; prazocin; rats; tonic pain
• ISSN: 0971-2119; 0974-1844
• DOI: 10.1080/09712119.2004.9706474

Taherianfard, M., Bahaoddini, A., Rajaian, H. and Dabbaghlotfi, A. 2004. IP injection of phenylephrine and prazocin on tonic pain during estrus cycle in rats. J. Appl. Anim. Res., 25: 53-55. To investigate the effect of αl receptor against and antagonist on tonic pain in all phases of estrus cycle in female rats, phenylephrine (αl receptor agonist) and prazocin (αl receptor antagonist) were administered intraperitoneally to adult female rats (200-220g). One group of rats with no injection was kept as control, whereas, another group was given saline in place of drugs. Formalin test was performed in all phases of estrus cycle. It was shown that phenylephrine causes significant (P<0.05) reduction in pain sensitivity, particularly during proestrus. Prazocin significantly (P<0.05) increased pain sensitivity, particularly during metestrus. It seems fluctuation in pain sensitivity during estrus cycle is related to the level of sex hormones during estrus cycle.