Neurological Terms beginning with P

Glossary of neurological terms
p25 search for term

is a protein whose overproduction is thought to lead to beta amyloid plaques, neurofibrillary tangles, and neuron loss. It is a fragment of another protein, p35, and can be formed when a stroke or some other unknown event breaks the p35. P25 alters the behavior of an enzyme, Cdk5, causing it to kill neurons.

p75NTR search for term

a receptor that in the body binds neurotrophins. There is some evidence that in Alzheimer's, some of the neurons that die express the p75NTR binding site, indicating they may be dying because neurotrophins are binding to them.

PAK search for term

p21-activated kinase -- a type of enzyme

PAK enzyme signaling pathways search for term

a critical part of the machinery that controls the connections between neurons; defects are implicated in both mental retardation and Alzheimer's

peptide search for term

a compound of two or more amino acids linked by a peptide bond. Peptides differ from proteins by their size; peptides are shorter. Proteins can be broken down into peptides (this occurs during digestion).

peroxisome-proliferator activated receptor search for term

receptors in the brain that controls insulin responses; stimulation of these has been found to reduce neurodegeneration of brain cells and preserve learning and memory in rats with induced Alzheimer's disease, raising the possibility that patients in the very early stages of Alzheimer’s might be treatable. PPAR alpha and PPAR gamma were effective in reducing amyloid gene expression, while PPAR delta had the most benefit for reducing oxidative stress and improving learning and memory. PPAR gamma is already FDA approved as a treatment for Type 2 diabetes.

Pin1 search for term

prolyl isomerase; an enzyme that helps prevent tangles and plaques.

Pittsburgh Compound B search for term

a compound that, through PET scanning, enables researchers to see the amyloid plaque deposits in the brains of Alzheimer’s sufferers.

polyphenols search for term

antioxidant chemicals that may help reduce the risk of Alzheimer's. Most exist primarily in the skins of fruits and vegetables and are particularly abundant in teas, juices and wines.

presenilins search for term

are related genes implicated in early-onset Alzheimer's. Presenilin 1 (PS1) is found on chromosome 14, and PS2 on chromosome 1. Presenilins are involved in the production of amyloid peptides, but exactly how mutations in the genes cause Alzheimer's is not yet understood. Mouse studies have found that deletion of these genes causes memory loss and gradual death of nerve cells in the mouse brain, demonstrating that the protein products of these genes are essential for normal learning, memory and nerve cell survival.

prion search for term

a protein that by changing shape (and thus function), induces neighboring proteins to do so too. Research indicates prions can speed up neurogenesis. Malformed prions cause mad cow disease.

progenitor cells search for term

multipurpose cells capable of proliferation but unable to self-renew like stem cells, and thus proliferate indefinitely.

progranulin search for term

is a protein growth factor that helps brain cells survive. A gene mutation that leads to a dramatic loss in production of progranulin has been implicated in frontotemporal dementia. Production of too much progranulin has been associated with cancer.

prospective memory search for term

memory for intentions, for actions we wish or expect to carry out in the future. It contrasts with retrospective memory, memory of the past.

proteases search for term

are enzymes that decompose peptide bonds, leading to the disassembly of proteins.

proteins search for term

are essential to living organisms; they are long chains of amino acids linked together by peptide bonds. Enzymes, hormones, and antibodies are all types of protein.

pyramidal neurons search for term

one of two main classes of neurons found in the cerebral cortex; so-called because of the shape of their dendritic branchings. They are excitatory neurons, that is they promote neuron firing (rather than inhibit it)