Separation of putative alpha 1A- and alpha 1B-adrenoceptor mediated components in the tension response of the rat vas deferens to electrical field stimulation
1. The effects of the putative alpha 1B-adrenoceptor antagonist, chloroethylchlonidine (CEC), on tension responses of the rat isolated whole vas deferens to single and multiple pulses of electrical field stimulation have been evaluated by use of a microcomputer system which enables the averaging of like-responses throughout their time course. 2. CEC (10(-7) to 3 x 10(-6) M) selectively and in a concentration-dependent manner blocked the noradrenergic component of the response to a single field stimulus in the absence or presence of nifedipine (10(-5) M, which blocked the purinergic but not the noradrenergic component of the response). The concentration-response curve of the vas to exogenously-applied noradrenaline (NA) was unaffected by CEC (10(-6) M) but was flattened by nifedipine (10(-5) M). 3. The tension response to 10 Hz trains of pulses was biphasic, with an early (less than 2 s) and a plateau (greater than 4 s) phase. We deduce from our pharmacological analysis that the early phase contains a putative alpha 1B-adrenoceptor component (susceptible to CEC or prazosin but not to nifedipine) and a P2-purinoceptor component (susceptible to suramin or nifedipine) whereas the plateau phase contains an alpha 1A-adrenoceptor component (susceptible to prazosin or nifedipine but not to CEC) and a P2-purinoceptor component (susceptible to suramin or nifedipine). 4. We suggest that the putative alpha 1B-adrenoceptors may be functionally confined to the synaptic region whereas the putative alpha 1A-adrenoceptors are excluded from this region. Trains of pulses would allow NA to accumulate and spill out beyond the synaptic region to reach and activate the putative alphalA-adrenoceptors.
| Medienart: |
Artikel |
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| Erscheinungsjahr: |
1992 |
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| Erschienen: |
1992 |
| Enthalten in: |
Zur Gesamtaufnahme - volume:105 |
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| Enthalten in: |
British journal of pharmacology - 105(1992), 3 vom: 13. März, Seite 727-31 |
| Sprache: |
Englisch |
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| Beteiligte Personen: |
Mallard, N J [VerfasserIn] |
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| Anmerkungen: |
Date Completed 20.08.1992 Date Revised 09.05.2019 published: Print Citation Status MEDLINE |
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| Förderinstitution / Projekttitel: |
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| PPN (Katalog-ID): |
NLM013021567 |
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| 041 | |a eng | ||
| 100 | 1 | |a Mallard, N J |e verfasserin |4 aut | |
| 245 | 1 | 0 | |a Separation of putative alpha 1A- and alpha 1B-adrenoceptor mediated components in the tension response of the rat vas deferens to electrical field stimulation |
| 264 | 1 | |c 1992 | |
| 336 | |a Text |b txt |2 rdacontent | ||
| 337 | |a ohne Hilfsmittel zu benutzen |b n |2 rdamedia | ||
| 338 | |a Band |b nc |2 rdacarrier | ||
| 500 | |a Date Completed 20.08.1992 | ||
| 500 | |a Date Revised 09.05.2019 | ||
| 500 | |a published: Print | ||
| 500 | |a Citation Status MEDLINE | ||
| 520 | |a 1. The effects of the putative alpha 1B-adrenoceptor antagonist, chloroethylchlonidine (CEC), on tension responses of the rat isolated whole vas deferens to single and multiple pulses of electrical field stimulation have been evaluated by use of a microcomputer system which enables the averaging of like-responses throughout their time course. 2. CEC (10(-7) to 3 x 10(-6) M) selectively and in a concentration-dependent manner blocked the noradrenergic component of the response to a single field stimulus in the absence or presence of nifedipine (10(-5) M, which blocked the purinergic but not the noradrenergic component of the response). The concentration-response curve of the vas to exogenously-applied noradrenaline (NA) was unaffected by CEC (10(-6) M) but was flattened by nifedipine (10(-5) M). 3. The tension response to 10 Hz trains of pulses was biphasic, with an early (less than 2 s) and a plateau (greater than 4 s) phase. We deduce from our pharmacological analysis that the early phase contains a putative alpha 1B-adrenoceptor component (susceptible to CEC or prazosin but not to nifedipine) and a P2-purinoceptor component (susceptible to suramin or nifedipine) whereas the plateau phase contains an alpha 1A-adrenoceptor component (susceptible to prazosin or nifedipine but not to CEC) and a P2-purinoceptor component (susceptible to suramin or nifedipine). 4. We suggest that the putative alpha 1B-adrenoceptors may be functionally confined to the synaptic region whereas the putative alpha 1A-adrenoceptors are excluded from this region. Trains of pulses would allow NA to accumulate and spill out beyond the synaptic region to reach and activate the putative alphalA-adrenoceptors | ||
| 650 | 4 | |a Journal Article | |
| 650 | 4 | |a Research Support, Non-U.S. Gov't | |
| 650 | 7 | |a Receptors, Adrenergic, alpha |2 NLM | |
| 650 | 7 | |a chlorethylclonidine |2 NLM | |
| 650 | 7 | |a 3X825O680H |2 NLM | |
| 650 | 7 | |a Suramin |2 NLM | |
| 650 | 7 | |a 6032D45BEM |2 NLM | |
| 650 | 7 | |a Nifedipine |2 NLM | |
| 650 | 7 | |a I9ZF7L6G2L |2 NLM | |
| 650 | 7 | |a Clonidine |2 NLM | |
| 650 | 7 | |a MN3L5RMN02 |2 NLM | |
| 650 | 7 | |a Norepinephrine |2 NLM | |
| 650 | 7 | |a X4W3ENH1CV |2 NLM | |
| 650 | 7 | |a Prazosin |2 NLM | |
| 650 | 7 | |a XM03YJ541D |2 NLM | |
| 700 | 1 | |a Marshall, R W |e verfasserin |4 aut | |
| 700 | 1 | |a Sithers, A J |e verfasserin |4 aut | |
| 700 | 1 | |a Spriggs, T L |e verfasserin |4 aut | |
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| 773 | 1 | 8 | |g volume:105 |g year:1992 |g number:3 |g day:13 |g month:03 |g pages:727-31 |
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