Studies in which the involvement of 5-HT1 or 5-HT2 heteroreceptors in modulation of DA release has been investigated in vitro Effects of 5-HT1 or 5-HT2 receptor ligands on DA release in the rat corpus striatum are shown.
| Species | Brain Region | Receptor Typea | Drugs | Release-Inhibiting Concentrations or pA10 of Antagonists | Comment | References |
|---|---|---|---|---|---|---|
| Rat | Striatum | 5-HT | 5-HT | pIC25 = 6.09 | Superfusion of slices; K+ (25 mM)-evoked [3H]DA release; pA10 values for antagonism of 5-MeOT-induced inhibitionb; inhibitory effect of 5-MeOT unaffected by TTX (0.1 μM) in the superfusion buffer | Ennis et al. (1981) |
| 5-MeOT | pIC25 = 6.45 | |||||
| 5-MeO-N,N-dimethyltryptamine | pIC25 = 6.45 | |||||
| Methysergide | pA10 = 8.26 2 | |||||
| Metergoline | pA10 = 7.06 2 | |||||
| Methiothepine | pA10 = 6.95 2 | |||||
| Cinanserin | pA10 = 6.80 2 | |||||
| Cyproheptadine | pA10 = 6.13 2 | |||||
| Mianserin | pA10 = 6.00 2 | |||||
| Rat | Striatum | 5-HT | 5-HT | 10–6–10–5 M | Superfusion of slices, electrically induced release of [3H]DA (5 Hz); superfusion in the presence of benztropine (10–6 M); reversal of 5-HT-induced inhibition by methysergide (1.7 × 10–5 M) | Westfall and Tittermary (1982) |
| Rat | Striatum | 5-HT2 | 5-HT | 3 × 10–7–10–6 M | Superfusion of slices; K+ (25 mM)-evoked [3H]DA release in vitro; inhibition (also in the presence of 0.1 μM TTX) reversed by minaprine (10–5 M), ketanserin (10–6 M), or mianserin (10–5 M) | Muramatsu et al. (1988b) |
| Rat | Striatum | 5-HT1B | 5-HT | 10–7–10–3 M | Incubation of synaptosomes; K+ (20 mM)-induced [3H]DA release inhibited by 5-HT and by the 5-HT1B agonist CP-93129; sumatriptan had no effect; the selective 5-HT1B receptor antagonist SB 224289 counteracted the inhibitory effects of 5-HT and CP-93129 | Sarhan and Fillion (1999) |
| CP-93,129 | 10–6–10–3 M | |||||
| Rat | Striatum | 5-HT1B | CP-93,129 | 10–8–10–4 M | Incubation of synaptosomes; K+ (20 mM)-induced [3H]DA release inhibited by 5-HT1B agonist CP-93129; the selective 5-HT1B receptor antagonist SB 224289 abolished inhibitory effect of CP-93129 with Ki = 1.8 × 10–9 M. | Sarhan et al. (1999) |
| Rat | Striatum | 5-HT1B | CP-93,129 | 10–7–10–3 M | Incubation of synaptosomes; K+ (20 mM)-induced [3H]DA release inhibited by 5-HT1B agonist CP-93129; SB 224289 abolished inhibitory effect of CP-93129; preincubation with a specific 5-HT1B receptor antibody or with 5-HT moduline (tetrapeptide LSAL) reduced the inhibitory effect of CP-93129 in a noncompetitive manner | Sarhan et al. (2000) |
| Mouse and 5-HT1B ko mouse | Striatum | 5-HT1B | CP-93,129 | 10–7–10–5 M | Incubation of synaptosomes; K+ (20 mM)-induced [3H]DA release studied; the selective 5-HT1B agonist CP-93129 caused inhibition of [3H]DA release in wild-type but had no effect in 5-HT1B ko mouse; the 5-HT1B/D/7 agonist sumatriptan had no effect in wild-type or in 5-HT1B ko mice; the selective 5-HT1B antagonist SB 224289 abolished inhibitory effect of CP-93129 in wild-type mice | Sarhan et al. (2000) |
| 5-CT | 10–7–10–5 M |
5-MeOT, 5-methoxytryptamine (5-HT4 agonist); 5-MeO-N,N-dimethyltryptamine, 5-methoxy-N,N-dimethyltryptamine (5-HT1A agonist); ko, knockout
↵ a Receptor type involved, as suggested by the authors
↵ b pA10, negative logarithm of the molar concentration of antagonist that increased the control IC25 of the agonist by a factor of 10