ISSN:
1435-1463
Keywords:
Striatum
;
dopamine receptor
;
desipramine
;
adaptive change
;
pertussis toxin
;
ADP-ribosylation
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Summary The response of adenylate cyclase to GTP and to dopamine (DA) was investigated in striatal membranes from desipramine (DMI)-treated rats (10mg/kg, b.i.d., for 5 days). GPT exerted the same biphasic effect on basal and DA-stimulated enzyme activity in membranes from DMI-treated rats as on saline-treated rats. Rats were injected intraventricularly once with islet activating protein (IAP), pertussis toxin, and given extended treatment with DMI in order to study the effects on the inhibitory GTP-binding protein (Gi). Gi loses its function as a signal transducer on being ADP-ribosylated selectively by the IAP. D2 inhibition of adenylate cyclase by DA was attenuated by the IAP treatment in both DMI- and saline-treated rats; peak levels of DA plus GTP stimulation shifted from 1 μM to 100 μM GTP. D1 stimulation of adenylate cyclase by DA was also attenuated by the IAP in the DMI-treated rats. Since long-term treatment with DMI (15mg/kg, once a day, for 3 weeks) resulted in suppression of D1 stimulation similar to that seen in the present findings, uncoupling between D2 receptors and Gi due to IAP treatment might accelerate DMI-induced adaptive changes of dual control of adenylate cyclase system by DA.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01277016
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