Functional involvement of protein kinase C, Rho-kinase and TRPC3 decreases while PLC increases with advancement of pregnancy in mediating oxytocin-induced myometrial contractions in water buffaloes (Bubalus bubalis)

Theriogenology. 2017 Apr 1:92:176-189. doi: 10.1016/j.theriogenology.2016.12.008. Epub 2016 Dec 7.

Abstract

Present study unravels the involvement of different calcium signaling pathways in oxytocin-induced contractions in myometrium of non-pregnant and pregnant buffaloes during early and mid-pregnancy stages. Uteri of pregnant animals were more sensitive than of non-pregnant buffaloes. Phasic contractions and frequency of contraction significantly increased with advancement of pregnancy, while tonic contractions non-significantly and amplitude significantly decreased from six months pregnancy onward. Oxytocin produced concentration-dependent-contraction on isolated myometrial strips of pregnant and non-pregnant buffaloes and the dose response curves (DRCs) of oxytocin were significantly (P < 0.05) shifted to right in the presence of nifedipine (1 μM), in Ca2+-free Ringer Locke solution (RLS), ruthenium red (30 μM), ruthenium red + nifedipine, cyclopiazonic acid (CPA; Ca2+ free RLS as well as RLS), CPA (10 μM)+nifedipine, U-73122 (1 μM) + nifedipine and SKF96365 (25 μM) on uteri of non-pregnant and pregnant (early and mid) animals. The DRCs were also significantly shifted towards right in the presence of Y-27632 (10 μM), GF109203X (5 μM) and Pyr3 (10 μM) on uteri of non-pregnant and early pregnancy stage buffaloes while only in the presence of U-73122 (1 μM) on uteri of mid-pregnancy stage buffaloes. Our finding suggest that and L-type Ca2+ channels, IP3-RyR-gated, and store-operated calcium channels including transient receptor potential channel (TRPC) pathways play significant role in mediating oxytocin-induced contractions in myometrium of pregnant and non-pregnant buffaloes. SERCA plays major role only during early-pregnancy while functional role of protein kinase C (PKC), Rho-kinase and TRPC3 pathways decreased and role of G-protein coupled receptor-phospholipase C (GPCR-PLC) pathway increased with advancement of pregnancy.

Keywords: Buffalo myometrium; Oxytocin; PKC; Phospholipase-C; Rho-kinase; Store-operated Ca(2+) channel/transient receptor potential channel.

MeSH terms

  • Animals
  • Buffaloes / physiology*
  • Calcium Channel Blockers / pharmacology
  • Enzyme Inhibitors / administration & dosage
  • Enzyme Inhibitors / pharmacology
  • Female
  • Gene Expression Regulation, Enzymologic
  • Imidazoles / pharmacology
  • Indicators and Reagents / pharmacology
  • Myometrium / drug effects*
  • Nifedipine / pharmacology
  • Oxytocin / pharmacology*
  • Pregnancy
  • Protein Kinase C / metabolism*
  • Pyrazoles / pharmacology
  • Ruthenium Red / pharmacology
  • TRPC Cation Channels / genetics
  • TRPC Cation Channels / metabolism*
  • Type C Phospholipases / genetics
  • Type C Phospholipases / metabolism
  • Uterine Contraction / drug effects
  • Uterine Contraction / physiology
  • Vasodilator Agents / administration & dosage
  • Vasodilator Agents / pharmacology
  • rho-Associated Kinases / metabolism*

Substances

  • Calcium Channel Blockers
  • Enzyme Inhibitors
  • Imidazoles
  • Indicators and Reagents
  • Pyrazoles
  • TRPC Cation Channels
  • TRPC3 cation channel
  • Vasodilator Agents
  • ethyl-1-(4-(2*3*3-trichloroacrylamide)phenyl)-5-(trifluoromethyl)-1H-pyrazole-4-carboxylate
  • Ruthenium Red
  • Oxytocin
  • rho-Associated Kinases
  • Protein Kinase C
  • Type C Phospholipases
  • 1-(2-(3-(4-methoxyphenyl)propoxy)-4-methoxyphenylethyl)-1H-imidazole
  • Nifedipine