+ Translate

Evidence that 8 hydroxy 2 n dipropylaminotetralin 8 oh dpat is a selective alpha 2 adrenoceptor antagonist on guinea pig submucous neurons

, : Evidence that 8 hydroxy 2 n dipropylaminotetralin 8 oh dpat is a selective alpha 2 adrenoceptor antagonist on guinea pig submucous neurons. British Journal of Pharmacology 92(2): 341-348

Intracellular recordings were made from neurones of the submucous plexus and from submucosal arteriolar smooth muscle of the guinea-pig ileum for the purpose of examining the actions of 8-hydroxy-2-(n-dipropylamino)tetralin (8-OH-DPAT). 8-OH-DPAT (10 nM-20 .mu.M) had no direct presynaptic or postsynaptic actions on submucous plexus neurones. Membrane hyperpolarizations induced in neurones by noradrenaline or UK 14304 were competitively antagonized by 8-OH-DPAT. For dose-ratios up to 40, Schild plots were linear with slopes not significantly different from unity; pA2, values for the 8-OH-DPAT antagonism of postsynaptic .alpha.2-adrenceptors were 6.9-7.2. The inhibitory synaptic potential, which is due to activation of .alpha.2-adrenoceptors located on submucous plexus neurones, was selectively inhibited by 8-OH-DPAT; the IC50 value for inhibition of the inhibitory synaptic potential was 250 nM. Neuronal hyperpolarizations mediated through activation of .delta.-opioid receptors or somatostatin receptors were unaffected by 8-OH-DPAT (0.1-1 .mu.M). The ability of noradrenaline and UK 14304 to inhibit the release of acetylcholine at synapses in the submucous plexus, and to inhibit the release of the transmitter which mediates the excitatory junction potential in the submucosal arteriolar smooth muscle, was also blocked by 8-OH-DPAT. These results suggests that some of the actions of 8-OH-DPAT previously ascribed to agonism at 5-hydroxytryptamine (5-HT)1 receptors may actually result from blockade of the actions of endogenously released noradrenaline acting on .alpha.2-adrenoceptors.

(PDF 0-2 workdays service)

Order PDF Full Text


Click here to order any other PDF Full Text

Accession: 005411967

PMID: 2890393

Submit PDF Full Text: Here

Submit PDF Full Text

No spam - Every submission is manually reviewed

Due to poor quality, we do not accept files from Researchgate

Submitted PDF Full Texts will always be free for everyone
(We only charge for PDFs that we need to acquire)

Select a PDF file:

Other references

Garty, B.; Kauli, R., 1982: Sexual development in the Prader-Labhart-Willi syndrome. Harefuah 103(1-2): 28-29

Knutson, J.H.; Lee, S.B.; Zhang, W.Q.; Selker, J.S., 1993: Fiberglass wick preparation for use in passive capillary wick soil pore-water samplers. Passive capillary samplers (PCAPS) use the capillary potential generated by hanging fiberglass wicks to exert a sampling suction on soil water. Impurities on the fiberglass affect the capillary properties of the wick and the chemical properties...

Odetunde, O.Israel.; Odetunde, O.Arinola.; Ademuyiwa, A.Oludotun.; Okafor, H.Uche.; Ekwochi, U.; Azubuike, J.Chukwuemeka.; Obianyo, N.Elsie., 2012: Outcome of late presentation of posterior urethral valves in a resource-limited economy: challenges in management. Delayed presentation of patients with posterior urethral valve with complications like severe urosepsis, uremia, and anemia are seen in our setting. Renal replacement therapy which should have been offered to these patients is not readily availabl...

Polubentseva E.I.; Anokhin V.N., 1986: The course and outcomes of rheumatic carditis clinico echocardiographic study. Revmatologiya (4): 3-10

Adler, N.E.; Milstein, A., 1983: Evaluating the impact of physician peer review: factors associated with successful PSROs. A five-component measurement method was developed and applied to the 1981 impact statements of 30 Professional Standards Review Organizations (PSROs) by four blind raters familiar with the PSRO program. High inter-rater reliability (.95) was achie...

Schmidt, M.G.; Konetzka, W.A., 1986: Glutathione overproduction by selenite-resistant Escherichia coli. Use of resistance to sodium selenite is an effective method for the selection of glutathione overproduction in Escherichia coli.

Swaisland, A.J.; Franklin, R.A.; White, A.C., 1979: The biotransformation of ciclazindol in man. British Journal of Clinical Pharmacology 7(1): 120-123

Anonymous, 1983: Historic national convention resolution: health policy program--in 18 clear points. Sykepleien 70(9): 8-8

Wanke A.; Melezhik Victor, 2005: Sedimentary and volcanic facies recording the Neoarchaean continent breakup and decline of the positive delta super 13 C sub carb excursion. The Palaeoproterozoic Kalix Greenstone Belt, at the northern end of the Bothnian Bay in Sweden, comprises three groups. The Lower group, a ca. 3000 m thick unit of subaerially erupted, tholeiitic, intraplate, basalts interbedded with fluviatile co...

Nash, T., 1970: Reactive transport of some toxic gases across the air-water interface. Annals of Occupational Hygiene 13(4): 213-217