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Predicate | Object |
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rdf:type | |
lifeskim:mentions | |
pubmed:issue |
2
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pubmed:dateCreated |
1984-10-12
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pubmed:abstractText |
Additional experimental evidence was obtained for an inhibitory function of prejunctional alpha 2-adrenoceptors and/or dopamine receptors located on noradrenergic neurons innervating the heart and resistance vessels of the pithed normotensive rat. Mixed alpha 2-adrenoceptor/dopamine receptor agonists, differing in selectivity towards either receptor type, i.e. N,N-di-n-propyldopamine (DPDA), 2-N, N-di-n-propylamino-6, 7-dihydroxy-1,2,3,4-tetrahydro-naphthalene (DP-6,7-ADTN), B-HT 920 and B-HT 933 (azepexole) were used. In pithed normotensive rats, DPDA (30 and 100 micrograms/kg/min) dose-dependently inhibited the electrical stimulation-induced increase in diastolic pressure, but did not significantly affect the stimulation-evoked increase in heart rate. The inhibition exerted by DPDA was blocked by haloperidol and sulpiride (0.3 mg/kg of each), but not by yohimbine (1 mg/kg), indicating the involvement of dopamine receptors. In this respect, sulpiride and haloperidol were found approximately equipotent. DP-6,7-ADTN (10 and 30 micrograms/kg/min) impaired both tachycardic and vasoconstrictor responses in a dose-dependent manner. Sulpiride (0.3 mg/kg) only partially restored the DP-6,7-ADTN-depressed stimulation-evoked increase in diastolic pressure, whereas yohimbine (1 mg/kg) alone was without effect. The combination of both antagonists completely prevented the inhibition caused by DP-6,7-ADTN. On the other hand, yohimbine (1 mg/kg), but not sulpiride (0.3 mg/kg), selectively antagonized the DP-6,7-ADTN-induced inhibition of stimulation-evoked tachycardia. B-HT 920 (1, 3 and 10 micrograms/kg/min) very effectively reduced the increase in diastolic pressure and heart rate caused by electrical stimulation.(ABSTRACT TRUNCATED AT 250 WORDS)
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pubmed:language |
eng
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pubmed:journal | |
pubmed:citationSubset |
IM
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pubmed:chemical | |
pubmed:status |
MEDLINE
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pubmed:month |
Jun
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pubmed:issn |
0028-1298
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pubmed:author | |
pubmed:issnType |
Print
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pubmed:volume |
326
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
91-8
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pubmed:dateRevised |
2003-11-14
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pubmed:meshHeading |
pubmed-meshheading:6089003-Adrenalectomy,
pubmed-meshheading:6089003-Animals,
pubmed-meshheading:6089003-Azepines,
pubmed-meshheading:6089003-Blood Pressure,
pubmed-meshheading:6089003-Cardiovascular System,
pubmed-meshheading:6089003-Electric Stimulation,
pubmed-meshheading:6089003-Heart Rate,
pubmed-meshheading:6089003-Male,
pubmed-meshheading:6089003-Neural Inhibition,
pubmed-meshheading:6089003-Neurons,
pubmed-meshheading:6089003-Rats,
pubmed-meshheading:6089003-Rats, Inbred Strains,
pubmed-meshheading:6089003-Receptors, Adrenergic, alpha,
pubmed-meshheading:6089003-Receptors, Dopamine,
pubmed-meshheading:6089003-Spinal Cord,
pubmed-meshheading:6089003-Sympathetic Nervous System,
pubmed-meshheading:6089003-Synapses
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pubmed:year |
1984
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pubmed:articleTitle |
Inhibitory dopamine receptors on sympathetic neurons innervating the cardiovascular system of the pithed rat. Characterization and role in relation to presynaptic alpha 2-adrenoceptors.
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pubmed:publicationType |
Journal Article
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