Testing the contributions of striatal dopamine loss to the genesis of parkinsonian signs

https://doi.org/10.1016/j.nbd.2012.03.028Get rights and content

Abstract

The diverse and independently-varying signs of Parkinson's disease (PD) are often attributed to one simple mechanism: degeneration of the dopaminergic innervation of the posterolateral striatum. However, growing recognition of the dopamine (DA) loss and other pathology in extra-striatal brain regions has led to uncertainty whether loss of DA in the striatum is sufficient to cause parkinsonian signs. We tested this hypothesis by infusing cis-flupenthixol (cis-flu; a broad-spectrum D1/D2 receptor antagonist) into different regions of the macaque putamen (3 hemispheres of 2 monkeys) while the animal performed a visually-cued choice reaction time task in which visual cues indicated the arm to reach with and the peripheral target to contact to obtain food reward. Following reward delivery, the animal was required to self-initiate release of the peripheral target and return of the chosen hand to its home position (i.e., without the benefit of external sensory cues or immediate rewards). Infusions of cis-flu at 15 of 26 sites induced prolongations of reaction time (9 of 15 cases), movement duration (6 cases), and/or dwell time of the hand at the peripheral target (8 cases). Dwell times were affected more severely (+ 95%) than visually-triggered reaction times or movement durations (+ 25% and + 15%, respectively). Specifically, the animal's hand often ‘froze’ at the peripheral target for up to 25-s, similar to the akinetic freezing episodes observed in PD patients. Across injections, slowing of self-initiation did not correlate in severity with prolongations of visually-triggered reaction time or movement duration, although the latter two were correlated with each other. Episodes of slowed self-initiation appeared primarily in the arm contralateral to the injected hemisphere and were not associated with increased muscle co-contraction or global alterations in behavioral state (i.e., inattention or reduced motivation), consistent with the idea that these episodes reflected a fundamental impairment of movement initiation. We found no evidence for an anatomic topography within the putamen for the effects elicited. We conclude that acute focal blockade of DA transmission in the putamen is sufficient to induce marked akinesia-like impairments. Furthermore, different classes of impairments can be induced independently, suggesting that specific parkinsonian signs have unique pathophysiologic substrates.

Highlights

► Is focal striatal dopamine loss sufficient to elicit parkinsonian signs in primates? ► D1/D2 antagonist infusion into putamen variably elicited akinesia and bradykinesia. ► Akinesia was most severe for self-initiated non-rewarded reaching movements. ► Acute focal blockade of putamenal dopamine is sufficient to induce akinesia. ► Elicting individual signs in isolation suggests they have distinct pathophysiologies.

Introduction

Given the spectacular therapeutic efficacy of dopamine-replacement therapies (Hornykiewicz and Kish, 1987), there is little doubt that the core motor signs of Parkinson's disease (akinesia, bradykinesia, rigidity and tremor) arise from a loss of dopamine (DA) in the central nervous system. Historically, loss of DA from the posterolateral striatum (i.e., the skeletomotor region of the putamen) has been thought to be the primary factor that leads to parkinsonism (Damier et al., 1999, Forno, 1996). Indeed, the largest loss of DA in absolute terms is from the posterior putamen (Ehringer and Hornykiewicz, 1960, Kish et al., 1988) and symptom severity does correlate with the level of putamenal DA depletion (Bernheimer et al., 1973, Morrish et al., 1996, Nandhagopal et al., 2009, Seibyl et al., 1995). Putamenal DA depletion, however, is not a perfect predictor of symptom severity or symptom progression in individual patients (Gallagher et al., 2011, Pavese et al., 2011, Pirker, 2003), suggesting that factors other than putamenal DA influence the genesis of parkinsonian symptoms. Dopamine loss in PD is not restricted to the striatum (reviewed by Rommelfanger and Wichmann, 2010), but has also been observed in the subthalamic nucleus, thalamus, globus pallidus, and cortex (Francois et al., 2000, Freeman et al., 2001, Jan et al., 2000, Scatton et al., 1982, Scatton et al., 1983). Thus, the minimal pathologic defect necessary to induce parkinsonian signs remains unknown.

The diverse topography of DA loss in PD is mirrored by a variety of motor signs, which can be broken down into relatively independent groupings (Parkinson, 1817). Akinesia is a multi-component sign, characterized by a poverty of willed movement, slowness to initiate sensory-triggered movement (i.e., lengthened reaction times, RTs), and particular difficulty initiating movements in the absence of external sensory cues (Flowers, 1976, Morris et al., 1996, Oliveira et al., 1997). Freezing episodes, a facet of akinesia characterized by a temporary inability to initiate movement (Fahn, 1995, Jankovic, 2008, Nieuwboer et al., 2009) are difficult to treat, but can often be overcome with the help of external sensory cues (Arias and Cudeiro, 2008, Dietz et al., 1990, Marchese et al., 2000, Praamstra et al., 1998). Bradykinesia refers exclusively to slowed execution of movement (measurable as prolonged movement durations, MDs, Hallett and Khoshbin, 1980), while rigidity and tremor manifest as increased muscular resistance to passive joint movement and involuntary 4–6 Hz tremulous movements of one or more body part, respectively (Jankovic, 2008). Each of these parkinsonian signs varies independently in severity, rate of progression, and response to therapy (Espay et al., 2009, Evarts et al., 1981, Jankovic, 2008, Jordan et al., 1992, Kimber et al., 1999, Kishore et al., 2007, Meyer, 1982, Nieuwboer et al., 1998, Selikhova et al., 2009, Temperli et al., 2003, Zetusky and Jankovic, 1985), implying that different parkinsonian signs may have unique pathophysiologic substrates. Similarly, the fact that anatomically-segregated regions of the striatum are devoted to skeletomotor, associative and limbic functions (Alexander et al., 1990, Kelly and Strick, 2004, Worbe et al., 2009) has prompted proposals that dissociable symptoms of PD arise from loss of DA from separate functional regions of the striatum (Alexander et al., 1986, Joel and Weiner, 1994, Wichmann et al., 2011). It is therefore important to determine whether DA loss in specific striatal regions elicits separate parkinsonian signs.

Here, we sought to establish whether acute focal blockade of striatal DA neurotransmission is sufficient to induce behavioral changes that reflect parkinsonian signs. This question is not amenable to current DA-targeted neurotoxin approaches (i.e., using 6-OHDA or MPTP, Emborg, 2007). Administration of these agents leads to degeneration of dopaminergic somata in the substantia nigra compacta (Oiwa et al., 2003, Sauer and Oertel, 1994) and of their extensive multi-nuclear axonal arborizations (Debeir et al., 2005, Freeman et al., 2001, Pifl et al., 1991) even when the neurotoxin is infused directly into the striatum (Debeir et al., 2005, Freeman et al., 2001). Neurotoxin models, therefore, cannot rule out the potential roles of extra-striatal DA loss, degeneration of the somata of dopaminergic neurons, or chronic DA depletion in the development of parkinsonian signs.

An alternative approach involves the selective blockade of DA receptors in the striatum. Infusions of DA receptor antagonists into the striatum are known to elicit catalepsy in rodents (Amalric and Koob, 1987, Ellenbroek et al., 1985, Hauber et al., 2001, Kaur et al., 1997, Salamone et al., 1993, Yoshida et al., 1994). It is difficult, however, to relate the cataleptic state, a nonspecific combination of abnormal posturing and immobility, to specific signs of human parkinsonism. To our knowledge, only one previous study examined the behavioral effects of intra-striatal DA blockade in non-human primates (Hikosaka et al., 2006). In that study, small intra-striatal infusions of D1- or D2-specific antagonists disrupted the normal relationship between oculomotor reaction times and size of rewards (Hikosaka et al., 2006), but overt signs of parkinsonism were not noted. By infusing large volumes of a non-specific D1/D2-receptor antagonist at various sites in the putamen, we tested whether acute blockade of striatal DA transmission is sufficient to cause changes in motor performance reflective of parkinsonian signs.

Section snippets

Animals and task

Two monkeys (Macaca mulatta; D, male ~ 7.5 kg; E, female ~ 6 kg) were used in the study. All aspects of animal care were in accord with the “National Institutes of Health Guide for the Care and Use of Laboratory Animals, the PHS Policy on the Humane Care and Use of Laboratory Animals, and the American Physiological Society’s Guiding Principles in the Care and Use of Animals”, and all procedures were approved by the institutional animal care and use committee. An animal was seated in a primate chair

Results

A total of 26 cis-flu injections were performed in three hemispheres across two monkeys (18 injections across two hemispheres in monkey D, 8 injections in one hemisphere in monkey E; Fig. 2B). Three saline injections into the putamen were also performed, one in each hemisphere (Table 1).

Discussion

For decades, the pathophysiology of PD has been routinely attributed to loss of DA from the skeletomotor region of the posterior putamen. It has become increasingly unclear, however, whether simple under-activation of DA receptors in this region is sufficient to induce Parkinsonian signs. Recent studies have suggested possible roles for loss of DA from non-skeletomotor striatal regions, chronic striatal DA depletion, and extra-striatal DA loss in the emergence of parkinsonian signs (Francois et

Conclusions

Our results indicate that acute, focal blockade of striatal DA receptors is sufficient to induce motor deficits reflective of specific parkinsonian signs. Intra-striatal infusion of a D1- and D2-receptor antagonist in awake, behaving macaques was found to slow the initiation of movement more than its execution. Paralleling observations in PD patients, the initiation of self-generated movements was impaired more severely than initiation of externally-cued movements. Additionally, motor deficits

Acknowledgments

We wish to thank Mary Watach and Angela Cowan for expert assistance with animal care and surgery. Dr. Benjamin Pasquereau provided invaluable advice and assistance throughout the project. Dr. Kwan-Jin Jung of the University of Pittsburgh Brain Imaging Research Center provided advanced directional image filtering of the MRI images that enhanced the contours of the basal ganglia. This research was supported by the National Institute of Neurological Disorders and Stroke at the National Institutes

References (123)

  • C. Francois

    Calbindin D-28k as a marker for the associative cortical territory of the striatum in macaque

    Brain Res.

    (1994)
  • C. Francois

    A stereotaxic atlas of the basal ganglia in macaques

    Brain Res. Bull.

    (1996)
  • C.R. Gerfen

    The neostriatal mosaic: Multiple levels of compartmental organization

    Trends Neurosci.

    (1992)
  • M. Inase

    Corticostriatal and corticosubthalamic input zones from the presupplementary motor area in the macaque monkey: comparison with the input zones from the supplementary motor area

    Brain Res.

    (1999)
  • D. Joel et al.

    The organization of the basal ganglia-thalamocortical circuits: open interconnected rather than closed segregated

    Neuroscience

    (1994)
  • S. Kaur

    MK 801 reverses haloperidol-induced catalepsy from both striatal and extrastriatal sites in the rat brain

    Eur. J. Pharmacol.

    (1997)
  • H. Kunzle

    Bilateral projections from precentral motor cortex to the putamen and other parts of the basal ganglia. An autoradiographic study in macaca fascicularis

    Brain Res.

    (1975)
  • K.E. Lyons et al.

    Deep brain stimulation and tremor

    Neurotherapeutics

    (2008)
  • R.F. Martin et al.

    A stereotaxic template atlas of the macaque brain for digital imaging and quantitative neuroanatomy

    NeuroImage

    (1996)
  • C.C. McIntyre et al.

    Network perspectives on the mechanisms of deep brain stimulation

    Neurobiol. Dis.

    (2010)
  • S. Miocinovic

    Stereotactic neurosurgical planning, recording, and visualization for deep brain stimulation in non-human primates

    J. Neurosci. Methods

    (2007)
  • A. Parent

    Calcium-binding proteins in primate basal ganglia

    Neurosci. Res.

    (1996)
  • N. Pavese

    Progression of monoaminergic dysfunction in Parkinson's disease: a longitudinal 18F-dopa PET study

    NeuroImage

    (2011)
  • C. Pifl

    Effect of 1-methyl-4-phenyl-1,2,3,6-tetrahydropoyridine on the regional distribution of brain monoamines in the rhesus monkey

    Neuroscience

    (1991)
  • J.D. Salamone

    The role of brain dopamine in response initiation: effects of haloperidol and regionally specific dopamine depletions on the local rate of instrumental responding

    Brain Res.

    (1993)
  • H. Sauer et al.

    Progressive degeneration of nigrostriatal dopamine neurons following intra-striatal terminal lesions with 6-hydroxydopamine: a combined retrograde tracing and immunocytochemical study in the rat

    Neuroscience

    (1994)
  • G. Alexander

    Parallel organization of functionally segregated circuits linking basal ganglia and cortex

    Annu. Rev. Neurosci.

    (1986)
  • G.E. Alexander

    Basal ganglia thalamo-cortical circuits: parallel substrates for motor, oculomotor, "prefrontal" and "limbic" functions

    Prog. Brain Res.

    (1990)
  • A.L. Alexander

    Factors affecting drug distribution through infusion. PD Online Research

    (2009)
  • M. Amalric et al.

    Depletion of dopamine in the caudate nucleus but not in nucleus accumbens impairs reaction-time performance in rats

    J. Neurosci.

    (1987)
  • B.J. Aragona

    Regional specificity in the real-time development of phasic dopamine transmission patterns during acquisition of a cue-cocaine association in rats

    Eur. J. Neurosci.

    (2009)
  • P. Arias et al.

    Effects of rhythmic sensory stimulation (auditory, visual) on gait in Parkinson's disease patients

    Exp. Brain Res.

    (2008)
  • P. Arias et al.

    Effect of rhythmic auditory stimulation on gait in Parkinsonian patients with and without freezing of gait

    PLoS One

    (2010)
  • M. Bachlin

    Wearable assistant for Parkinson's disease patients with the freezing of gait symptom

    IEEE Trans. Inf. Technol. Biomed.

    (2010)
  • H. Bergman

    The primate subthalamic nucleus. II. Neuronal activity in the MPTP model of parkinsonism

    J. Neurophysiol.

    (1994)
  • M. Bronfeld

    Spatial and temporal properties of tic-related neuronal activity in the cortico-basal ganglia loop

    J. Neurosci.

    (2011)
  • J.D. Cooke

    Increased dependence on visual information for movement control in patients with Parkinson's disease

    Can. J. Neurol. Sci.

    (1978)
  • J.A. Cooper

    Cognitive impairment in early, untreated Parkinson's disease and its relationship to motor disability

    Brain

    (1991)
  • L.M. Cunningham

    A review of assistive technologies for people with Parkinson's disease

    Technol. Health Care

    (2009)
  • P. Damier

    The substantia nigra of the human brain. II. Patterns of loss of dopamine-containing neurons in Parkinson's disease

    Brain

    (1999)
  • M.R. DeLong et al.

    Circuits and circuit disorders of the basal ganglia

    Arch. Neurol.

    (2007)
  • M. Desmurget et al.

    Testing Basal Ganglia motor functions through reversible inactivations in the posterior internal globus pallidus

    J. Neurophysiol.

    (2008)
  • M.A. Dietz

    Evaluation of a modified inverted walking stick as a treatment for parkinsonian freezing episodes

    Mov. Disord.

    (1990)
  • B. Dubois et al.

    Cognitive deficits in Parkinson's disease

    J. Neurol.

    (1997)
  • H. Ehringer et al.

    Verteilung von noradrenalin und dopamin (3-hydroxytyramin) im gehirn des menschen und ihr verhalten bei erkrankungen des extrapyramidalen systems

    Klin. Wochenschr.

    (1960)
  • M.E. Emborg

    Nonhuman primate models of Parkinson's disease

    ILAR J.

    (2007)
  • A.J. Espay

    Impairments of speed and amplitude of movement in Parkinson's disease: a pilot study

    Mov. Disord.

    (2009)
  • E.V. Evarts

    Reaction time in Parkinson's disease

    Brain

    (1981)
  • S. Fahn

    The freezing phenomenon in parkinsonism

    Adv. Neurol.

    (1995)
  • A.W. Flaherty et al.

    Corticostriatal transformations in the primate somatosensory sstem. Projections from physiologically mapped body-part representations

    J. Neurophysiol.

    (1991)
  • Cited by (15)

    • The antiparkinson drug ropinirole inhibits movement in a Parkinson's disease mouse model with residual dopamine neurons

      2020, Experimental Neurology
      Citation Excerpt :

      One may argue that our observations were made in mice and hence may not be applicable to human PD patients. However, literature data have firmly established that DA critically stimulates motor function in all vertebrate animals (Grillner and Robertson, 2016), and the profound DA dependence of motor function in mammalian animals is amply demonstrated by the motor function loss caused by toxin-induced DA loss in rodents, monkeys and humans (Langston, 2017; Liang et al., 2008; Nonnekes et al., 2018; Schwarting and Huston, 1996), by DA receptor blockade (Franco and Turner, 2012), and by TH deletion (Zhou and Palmiter, 1995). Indeed, clinical opinions are swinging back in favor of L-dopa over DA agonists (Chaudhuri et al., 2019; Olanow, 2019).

    • The striatal medium spiny neurons: What they are and how they link with Parkinson’s disease

      2020, Genetics, Neurology, Behavior, and Diet in Parkinson’s Disease: The Neuroscience of Parkinson’s Disease, Volume 2
    • Nanoformulation: A Useful Therapeutic Strategy for Improving Neuroprotection and the Neurorestorative Potential in Experimental Models of Parkinson's Disease

      2017, International Review of Neurobiology
      Citation Excerpt :

      Accordingly, novel evidence supports the high dopamine reserve of striatum owing to the compensatory response by the collateral axonal sprouting from the surviving dopaminergic neurons and by the postsynaptic cells of the striatum (Arkadir, Bergman, & Fahn, 2014; Deumens et al., 2002). On the other hand a direct administration of the toxin into the striatum in a fixed stereotaxic coordinates produces a selective destruction of the dopaminergic system inducing a denervation of the posterolateral striatum and the subsequent loss of dopaminergic neurons in SN (Franco & Turner, 2012). This lesion provides a suitable partial model to elucidate the optimal time to initialize the treatment (Agid, Javoy, & Glowinski, 1973; Jankovic, Shoulson, & Weiner, 1994; Przedborski et al., 1991; Sarre et al., 2004).

    • The Substantia Nigra Pars Reticulata

      2016, Handbook of Behavioral Neuroscience
      Citation Excerpt :

      Future studies are needed to determine if D1-MSNs in different striatal subregions converge onto the same SNr GABA neurons. The nigrostriatal DA system has profound motor-stimulating effects: animals including humans immediately become akinetic when DA is depleted and quickly regain their mobility when DA is restored (Ballard et al., 1985; Franco and Turner, 2012; Li and Zhou, 2013). D1Rs on the D1-MSN somata, dendrites, and striatonigral axon terminals all contribute to the DA's motor stimulation and other behavioral effects.

    • Dissociable effects of dopamine on learning and performance within sensorimotor striatum

      2014, Basal Ganglia
      Citation Excerpt :

      Bilateral intrastriatal infusions of amphetamine post-training have been found to improve retention for certain types of tasks [42]. Unilateral putaminal dopamine receptor blockade in nonhuman primates induces contralateral parkinsonism [43]. Finally, intra-caudate infusion of D1 or D2 antagonists modifies the apparent effects of reward expectation on reaction time (RT) [44].

    View all citing articles on Scopus
    View full text