These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Evidence for two distinct P2-purinoceptors subserving contraction of the rat anococcygeus smooth muscle.
    Author: Najbar AT, Li CG, Rand MJ.
    Journal: Br J Pharmacol; 1996 Jun; 118(3):537-42. PubMed ID: 8762075.
    Abstract:
    1. The effects of the P2-purinoceptor agonists, adenosine 5'-triphosphate (ATP), alpha, beta-methylene ATP (alpha, beta-MeATP), beta, gamma-methylene ATP (beta, gamma-MeATP), L-beta, gamma-methylene ATP (L-beta, gamma-MeATP), adenosine-5'-O-(2-thiodiphosphate) (ADP beta S), and 2-methylthio ATP (2-MeSATP) were investigated on the isometric tension of the rat anococcygeus muscle. 2. Non-cumulative additions of ATP (100-1500 microM), alpha, beta-MeATP (1-300 microM), beta, gamma-MeATP (10-300 microM), L-beta, gamma-MeATP (3-100 microM) and ADP beta S (1-100 microM) produced concentration-dependent contractions, whereas 2-MeSATP (1-100 microM) had no effect. The rank order of potency was alpha, beta-MeATP > L-beta, gamma-MeATP > or = ADP beta S > beta, gamma-MeATP > > ATP > 2-MeSATP. 3. Contractions to cumulative additions of ATP, alpha, beta-MeATP, beta, gamma-MeATP and L-beta, gamma-MeATP were subject to desensitization whilst those to ADP beta S were unaffected. 4. Contractions to ATP, alpha, beta-MeATP, beta, gamma-MeATP and ADP beta S were abolished by the non-selective P2X/. P2Y-purinoceptor antagonist, suramin (100 microM). In contrast, contractions to ATP, alpha, beta-MeATP and beta, gamma-MeATP were not affected by the non-selective P1-purinoceptor antagonist 8-(p-sulphophenyl)-theophylline (8SPT, 30 microM). Blockade of P2X-purinoceptors with the selective P2X-purinoceptor antagonist pyridoxal-phosphate-6-azophenyl-2',4'-disulphonic acid (PPADS, 10 microM) or desensitization with L-beta, gamma-MeATP (10 microM) abolished contractions to alpha, beta-MeATP, but enhanced those to ADP beta S. The P2Y-purinoceptor antagonist, reactive blue 2 (RB2, 100 microM) enhanced contractions to ATP and alpha, beta-MeATP but abolished those to ADP beta S. 5. Simultaneous addition of alpha, beta-MeATP and ADP beta S produced an additive contraction. 6. The findings suggest that in the rat anococcygeus, smooth muscle cells are endowed with two distinct P2-purinoceptors which subserve contractions: a P2X-purinoceptor activated by ATP and its analogues, and another type of P2-purinoceptor activated by ADP beta S.
    [Abstract] [Full Text] [Related] [New Search]