Anticholinergics: Drugs that block the action of the neurotransmitter acetylcholine, thus rebalancing the brain in relation to dopamine. They can reduce tremor and rigidity. Artane and Cogentin are anticholinergics.
Basal ganglia: Groups of cells in the grey matter of each half of the brain which coordinate automatic movements. It comprises various specialised groups of cells, or nuclei, such as the globus pallidus and the substantia nigra.
Bradykinesia: A term used to describe slowness of motion and delayed initiation of movement, which is common in early stages of PD.
Cell line (fibroblasts, glial) cultivation: The development of a line of the patient's own cells (usually a type of cell known as a fibroblast, which is found in the brain's connective tissue or glial cells) and their modification into nerve cells. These would then be implanted in the brain to function in the substantia nigra as dopamine-releasing cells.
COMT Inhibitor: COMT (catech-o-methyl-transferase) inhibitors are drugs which help to prevent the mopping up of dopamine in the brain, thus allowing it to act for longer, and reducing "offs". Comtess is one such drug.
Dopamine Agonist: A drug which increases neurotransmittor activity by stimulating the dopamine receptors directly.
Dyskinesia: The most common and disruptive side-effect of PD therapy, dyskinesia is an involuntary movement that can accompany peak doses of levodopa.
Dystonia: Involuntary spasms of muscle contraction that cause abnormal movements and postures. The dystonia that occurs most frequently in PD is in the foot and is a characteristic of PD.
GDNF: Glial Derived Neurotrophic Factor is a nerve cell growth factor which in animal trials has been shown to stimulate the growth of many types of neurons.
Globus pallidus: A small part of the corpus striatum that is partly destroyed during pallidotomy. It regulates muscle tone needed for specific body movements.
Glutamate (NMDA) Antagonists: In a normal brain, neurons release a common neurotransmitter called glutamate. It is abundant throughout the brain, playing a role in communication between the various types of neurons. Without glutamate, the brain would seize up and cease to function. Researchers have determined over the past few years that for Parkinson's patients, insufficient levels of dopamine induce one tiny group of cells in the basal ganglia, called the subthalamic nucleus, to dramatically increase their activity. This hyperactivity means they produce extra glutamate -- so much that it overloads the glutamate receptors. Glutamate antagonists work by blocking the activity of some of these receptors, thus restoring more of a balance.
Hemiparesis: Partial or complete paralysis on one side of the body.
Lewy body: A pink-staining sphere found in the bodies of dying cells, that is thought to be a marker for Parkinson's Disease
MadoparŪ: A formulation combining levodopa and benserazide. MadoparŪ is available as a normal-release capsule, which provides rapid motor control, a controlled release preparation, which allows sustained control, and as a dispersible preparation that produces a drinkable formulation.
MAOI: Monoamine oxidase (MAO) is an enzyme that breaks down dopamine. In PD, a MAOI-B inhibitor can be taken to help reduce the breakdown of dopamine. Selegiline (Eldepryl, Clondepryl, Deprenyl) is a MAO-B inhibitor.
Microtubules: Any of the slender, tubular structures found in most cells, which are involved in maintenance of cell shape.
Mitochondria: These are the principal sites of detoxification, and it is suggested that in PD these do not work properly.
'On'-time: The period during which patients with PD adequately control their movements.
'Off'-time: The period during which patients with PD experience partial or total immobility.
Pallidotomy: A surgical operation in which surgeons destroy small areas of the globus pallidus in order to alleviate some of the symptoms of PD.
Porcine Tissue Implants: Implantation of embryonic pig cells.
Resting tremor: Shaking that occurs in a relaxed limb. It usually stops when a voluntary movement of the affected limb is made.
Rigidity: Resistance to manipulation of a limb. Cogwheel rigidity, a characteristic of PD, occurs when rigidity is combined with tremor.
SinemetŪ: A formulation combining levodopa and carbidopa.
Stereotactic surgery: A surgical technique in which surgeons use three dimensional co-ordinates to locate specific areas of the brain. Pallidotomy, thalamotomy and sub-thalamic stimulation use stereotactic techniques to locate the globus pallidus and thalamus and sub-thalamic nucleus respectively.
Substantia nigra: A region of the basal ganglia that is rich in dopamine-containing neurones. Its name, literally meaning black substance, comes from the black appearance seen post-mortem.
Synapse: The synapse is the space between the axon terminal of one neuron and the dendrite receptor of another (very simply, between the end of one neuron and the beginning of another). If a signal is to pass from one neuron to another, it must cross this gap. It does this by means of a chemical called a neurotransmitter, which allows electrical impulses to pass across the synapse from one neuron to another. Dopamine is one such neurotransmittor, and the slowing down in the production of dopamine is what causes the symptoms of PD.
Thalamotomy: A surgical operation in which surgeons destroy small areas of the thalamus in order to alleviate one-sided tremor.
Sub-Thalamic Stimulation: A surgical operation in which a thin wire probe is inserted into the sub-thalamic nucleus, an area of the brain which helps to control movement. This wire is connected to a device similar to a pacemaker, which is placed under the skin of the patient's chest. Electrical signals are sent from this to the sub-thalamus. The patient may switch the device on or off.
Thalamus: A small bundle of tissue located in the midbrain grey matter that is destroyed during thalamotomy. It is the main relay station for sensory impulses that reach the brain cortex from other parts of the brain and the spinal cord.
Tremor: Involuntary shaking.
Trophic Agents: These are trophic or growth factors that may help nerve cells, or parts of them, to grow. If tissue known to have trophic factors is transplanted into the brain, the trophic factors may help the transplanted tissue to survive.
Unilateral: Occurring on one side of the body.
Wearing off: A phenomenon characterized by a progressive shortening of 'on'-time following a dose of levodopa.

Section One: Parkinson's Disease | Section Two: Current Treatments | Section Three: Starting Treatment