Intrathecally administered apomorphine or LY171555 reduces nociceptive responses recorded from ventrobasal thalamic neurones in urethane anaesthetised rats.
The effects of intrathecal injections of the D2 agonists apomorphine and LY171555 were studied on responses of ventrobasal neurones responding to noxious stimulation in the urethane anaesthetised rat. At a dose of 75 micrograms/kg the D2 agonists had little effect on a total of 18 thalamic neurones. A higher dose (100 micrograms/kg) produced a reversible reduction of thalamic nociceptive responses on 15 occasions. A transient fall in blood pressure usually accompanied the intrathecal injection of the agonists. These results suggest that dopamine can modulate the transmission of nociceptive information to the thalamus and also suggests a role in the processing of autonomic function.
D000344:Afferent Pathways / Q000503:physiopathology; D000768:Anesthesia, General; D000818:Animals; D001058:Apomorphine / Q000494:pharmacology*; D004873:Ergolines / Q000494:pharmacology*; D007278:Injections, Spinal; D008297:Male; D010146:Pain / Q000503:physiopathology*; D019257:Quinpirole; D051381:Rats; D011919:Rats, Inbred Strains; D011954:Receptors, Dopamine / Q000502:physiology*; D017448:Receptors, Dopamine D2; D013116:Spinal Cord / Q000503:physiopathology*; D013788:Thalamus / Q000503:physiopathology*; D014520:Urethane / Q000494:pharmacology
D004873:Ergolines; D011954:Receptors, Dopamine; D017448:Receptors, Dopamine D2; D019257:Quinpirole; D014520:Urethane; D001058:Apomorphine