RT Journal Article
SR Electronic
T1 Identification of 5-hydroxytryptamine7 receptor binding sites in rat hypothalamus: sensitivity to chronic antidepressant treatment.
JF Molecular Pharmacology
JO Mol Pharmacol
FD American Society for Pharmacology and Experimental Therapeutics
SP 99
OP 103
VO 47
IS 1
A1 Sleight, A J
A1 Carolo, C
A1 Petit, N
A1 Zwingelstein, C
A1 Bourson, A
YR 1995
UL http://molpharm.aspetjournals.org/content/47/1/99.abstract
AB Due to the high level of expression of mRNA for the 5-hydroxytrytamine (5-ht7) receptor in the hypothalamus and the high affinity of 5-HT for this receptor, [3H]5-HT binding was performed in rat hypothalamus to determine whether 5-ht7 receptor binding sites are present in animal tissue. [3H]5-HT binding was performed in the presence of 100 nM pindolol, which is inactive at 5-ht7 receptors but prevents the binding of [3H]5-HT to 5-HT1A and 5-HT1B receptor binding sites. Under these conditions, [3H]5-HT bound to a binding site with an affinity of 1.94 nM. Displacement studies showed the pharmacology of the hypothalamic binding site to correlate well with the published pharmacology of the 5-ht7 receptor (r = 0.921). The treatment of rats with fluoxetine (5 mg/kg/day, orally) for 21 days caused a significant reduction in the number of hypothalamic 5-ht7 receptor binding sites. These data suggest that the 5-ht7 receptor binding site is expressed in rat hypothalamus and that this receptor binding site is down-regulated after a chronic increase in the synaptic level of 5-HT.