Striatal and nigral D 1 mechanisms involved in the antiparkinsonian effects of SKF 82958 (APB): studies of tremulous jaw movements in rats

Abstract

These data suggest that the antiparkinsonian actions of SKF 82958 may be due to stimulation of D1 receptors in the ventrolateral striatum and substantia nigra pars reticulata. In addition, these results indicate that GABA mechanisms in the substantia nigra pars reticulata may be important for the antiparkinsonian effects of D1 agonists.

Changes in Muscle Tone Are Regulated by D1 and D2 Dopamine Receptors in the Ventral Striatum and D1 Receptors in the Substantia Nigra

“…In terms of the role of D1 receptors in the ventral striatum and substantia nigra, recent findings have demonstrated that they regulate pilocarpine-induced jaw movements (Mayorga et al 1999). Further, it has been reported that D1 receptors in these regions are involved in the production of motor behaviors, such as dopamine agonist-induced stereotypy or catalepsy (Arnt 1985;Ossowska et al 1990;Wardas et al 1995).…”

“…In addition, in a previous study we showed increased EMG activity was associated with ‫%07ف‬ inactivation of both D1 and D2 receptor subfamilies in the substantia nigra (Hemsley and Crocker 1998). The current findings suggest that the effect of intranigral injection of EEDQ on muscle tone is solely due to inactivation of nigral D1 receptors because selective antagonism of D1 receptors resulted in increased EMG activity, whereas blockade of D2 receptors had no effect.In terms of the role of D1 receptors in the ventral striatum and substantia nigra, recent findings have demonstrated that they regulate pilocarpine-induced jaw movements (Mayorga et al 1999). Further, it has been reported that D1 receptors in these regions are involved in the production of motor behaviors, such as dopamine agonist-induced stereotypy or catalepsy (Arnt 1985;Ossowska et al 1990;Wardas et al 1995).…”

Motor Stimulant Effects of Ethanol Injected into the Substantia Nigra Pars Reticulata: Importance of Catalase-Mediated Metabolism and the Role of Acetaldehyde

“…One of the brain areas at which GABA mechanisms exert a powerful control over locomotion is the substantia nigra pars reticulata (SNr). SNr is a part of the basal ganglia circuitry that has been implicated in several types of motor activity, including muscle rigidity (Crocker, 1997), lever pressing (Trevitt et al, 2001;Correa et al, 2003c), tremor (Finn et al, 1997;Mayorga et al, 1999;Carlson et al, 2003a, b), catalepsy (Scheel-Kruger et al, 1977), circling (Scheel-Kruger et al, 1977), and locomotion (Scheel-Kruger et al, 1977Abraini et al, 1999;Trevitt et al, 2002). Although the SNr was once viewed as a region that simply provided feedback regulation of dopamine neurons in the substantia nigra pars compacta, it has become evident in the last few years that the SNr is one of the two major output nuclei for the basal ganglia (Scheel-Kruger et al, 1981;Young and Penney, 1993;Bevan et al, 1996;Wichmann et al, 1999).…”

“…SNr is a brain site at which several neurotransmitter systems interact to regulate motor activity. Interactions between dopamine D1 and GABA A receptors in SNr regulate various aspects of motor activity (Mayorga et al, 1999;Trevitt et al, 2002). GABAergic manipulation of the SNr produced profound effects on various aspects of motor activity (Scheel-Kruger et al, 1977.…”

“…Moreover, SNr is a brain area at which GABA A agonists and antagonists exert very potent effects on locomotion (Trevitt et al, 2002). Drugs that act on GABA A receptors are very potent at modifying motor output when injected locally into SNr, with effects at doses as low as 6 ng for the GABA A agonist muscimol (Finn et al, 1997;Trevitt et al, 2002), and 12-18 ng for the GABA A antagonist bicuculline (Mayorga et al, 1999;Trevitt et al, 2002;Correa et al, 2003c).…”