Pharmacology in vivo of the phenylindan derivative, lu 19-005, a new potent inhibitor of dopamine, noradrenaline and 5-hydroxytryptamine uptake in rat brain

Summary

Behavioural effects on dopaminergic transmission of a phenylindane derivative, Lu 19-005 [(±)-trans-3-(3,4-dichlorophenyl)-N-methyl-l-indanamine, HCl], with potent inhibitory effect on dopamine (DA), noradrenaline (NA) and serotonin (5-HT) uptake in rats and the effect on DA, NA and 5-HT activity in mice have been studied and compared with those of other known DA, NA and 5-HT uptake inhibitors with different selectivity ratios.

Lu 19-005 induced stereotyped behaviour after parenteral and oral administration with a duration of action of more than 24 h. The stereotyped licking and biting induced by Lu 19-005 was antagonized by reserpine and cis(Z)-flupentixol, but not affected by prazosin, p-chlorophenylalanine and α-methyl-p-tyrosine pretreatments. Metergoline slightly facilitated the onset of stereotypy. Lower doses of Lu 19-005 induced ipsilateral circling in unilaterally 6-hydroxy-DA-lesioned rats. Finally, Lu 19-005 antagonized the catalepsy induced by perphenazine. In mice, Lu 19-005 potentiated the apomorphine-induced gnawing, reversed tetrabenazine-induced ptosis and potentiated the behavioural effects of 5-HTP within a similar dose range.

The effects of Lu 19-005 were compared with those of other reference compounds. Nomifensine had qualitatively similar effects in rats although of much shorter duration. In mice, nomifensine selectively reversed tetrabenazine-induced ptosis. Weaker effects in all test models were found with bupropion, LR 5182 and GBR 13.069, compounds with inhibitory effect on DA and NA uptake. The DA-, NA-and 5-HT-uptake inhibitor diclofensine, however, had no effect in rats except in the 6-hydroxy-DA-circling test and had low potency in mice. The specific 5-HT-and NA-uptake inhibitors citalopram and talsupram, respectively, were ineffective in all rat models. They selectively potentiated 5-HTP or reversed tetrabenazine0induced ptosis in mice, respectively, as expected according to their in vitro profile. These results indicate that effect on DA mechanisms are responsible for the behavioural activity of the test compounds in the rat models and that the circling model is the most sensitive. Since DA may be involved in some depressive states Lu 19-005 could be an attaactive new antidepressant as it combines the pharmacological profile of established antidepressants (effect on NA and/or 5-HT uptake) with equipotent activity on DA uptake.