Abstract
Three selective α(2A)- or α(2B)-adrenergic antagonists (BRL-44408, BRL-41992 and imiloxan) were used in the present study designed to classify the presynaptic α2-auto- and heteroreceptors in the rat brain cortex. The rank order of potency in antagonizing the inhibitory effect of (-)-noradrenaline or clonidine on the K+-induced [3H]noradrenaline and [3H]5-hydroxytryptamine (5-HT) release from superfused synaptosomes was BRL-44408 ≥ BRL-41992 >> imiloxan. The same rank order was found for the affinities of these compounds for [3H]yohimbine binding in human platelet membranes, containing only α(2A)-adrenoceptors, but does not correlate with the known affinities for α(2B)-adrenoceptors (BRL-41992 ≥ imiloxan > BRL-44408). These data support the conclusion that presynaptic α2-auto- and heteroreceptors in rat brain cortex do not belong to the α(2B)-subtype and suggest that the modulation of noradrenaline and 5-HT release may be mediated by the α(2A)-subtype.
| Original language | English |
|---|---|
| Pages (from-to) | 811-814 |
| Number of pages | 4 |
| Journal | Journal of Pharmacy and Pharmacology |
| Volume | 45 |
| Issue number | 9 |
| Publication status | Published - 1993 |
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ASJC Scopus subject areas
- Pharmaceutical Science
- Pharmacology
Cite this
Further studies on α2-adrenoceptor subtypes involved in the modulation of [3H]noradrenaline and [3H]5-hydroxytryptamine release from rat brain cortex synaptosomes. / Gobbi, M.; Frittoli, E.; Mennini, T.
In: Journal of Pharmacy and Pharmacology, Vol. 45, No. 9, 1993, p. 811-814.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Further studies on α2-adrenoceptor subtypes involved in the modulation of [3H]noradrenaline and [3H]5-hydroxytryptamine release from rat brain cortex synaptosomes
AU - Gobbi, M.
AU - Frittoli, E.
AU - Mennini, T.
PY - 1993
Y1 - 1993
N2 - Three selective α(2A)- or α(2B)-adrenergic antagonists (BRL-44408, BRL-41992 and imiloxan) were used in the present study designed to classify the presynaptic α2-auto- and heteroreceptors in the rat brain cortex. The rank order of potency in antagonizing the inhibitory effect of (-)-noradrenaline or clonidine on the K+-induced [3H]noradrenaline and [3H]5-hydroxytryptamine (5-HT) release from superfused synaptosomes was BRL-44408 ≥ BRL-41992 >> imiloxan. The same rank order was found for the affinities of these compounds for [3H]yohimbine binding in human platelet membranes, containing only α(2A)-adrenoceptors, but does not correlate with the known affinities for α(2B)-adrenoceptors (BRL-41992 ≥ imiloxan > BRL-44408). These data support the conclusion that presynaptic α2-auto- and heteroreceptors in rat brain cortex do not belong to the α(2B)-subtype and suggest that the modulation of noradrenaline and 5-HT release may be mediated by the α(2A)-subtype.
AB - Three selective α(2A)- or α(2B)-adrenergic antagonists (BRL-44408, BRL-41992 and imiloxan) were used in the present study designed to classify the presynaptic α2-auto- and heteroreceptors in the rat brain cortex. The rank order of potency in antagonizing the inhibitory effect of (-)-noradrenaline or clonidine on the K+-induced [3H]noradrenaline and [3H]5-hydroxytryptamine (5-HT) release from superfused synaptosomes was BRL-44408 ≥ BRL-41992 >> imiloxan. The same rank order was found for the affinities of these compounds for [3H]yohimbine binding in human platelet membranes, containing only α(2A)-adrenoceptors, but does not correlate with the known affinities for α(2B)-adrenoceptors (BRL-41992 ≥ imiloxan > BRL-44408). These data support the conclusion that presynaptic α2-auto- and heteroreceptors in rat brain cortex do not belong to the α(2B)-subtype and suggest that the modulation of noradrenaline and 5-HT release may be mediated by the α(2A)-subtype.
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M3 - Article
VL - 45
SP - 811
EP - 814
JO - Journal of Pharmacy and Pharmacology
JF - Journal of Pharmacy and Pharmacology
SN - 0022-3573
IS - 9
ER -