| postsynaptic potential | In a synapse, a change in the resting potential of a postsynaptic cell following stimulation of the presynaptic cell. For example: in a cholinergic synapse, the release of acetylcholine from the presynaptic cell causes channels to open in the postsynaptic cell. Each channel opening causes a small depolarisation, known as a miniature end plate potential (mepp), these sum to produce an excitatory postsynaptic potential. (18 Nov 1997) |
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| inhibitory postsynaptic potential | The change in potential produced in the membrane of the next neuron when an impulse which has an inhibitory influence arrives at the synapse; it is a local change in the direction of hyperpolarization; the frequency of discharge of a given neuron is determined by the extent to which impulses that lead to excitatory postsynaptic potential's predominate over those that cause inhibitory postsynaptic potential's. (05 Mar 2000) |
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| excitatory postsynaptic potential | The change in potential which is produced in the membrane of the next neuron when an impulse which has an excitatory influence arrives at the synapse; it is a local change in the direction of depolarisation; summation of these potential's can lead to discharge of an impulse by the neuron. (05 Mar 2000) |
| postsynaptic | Pertaining to the area on the distal side of a synaptic cleft. (05 Mar 2000) |
| postsynaptic cell | In a chemical synapse, the cell that receives a signal (binds neurotransmitter) from the presynaptic cell and responds with depolarisation In an electrical synapse, the postsynaptic cell would just be downstream, but since many electrical synapses are rectifying, one of the two cells involved will always be postsynaptic. (18 Nov 1997) |
| postsynaptic membrane | That part of the plasma membrane of a neuron or muscle fibre with which an axon terminal forms a synaptic junction; in many instances, at least part of such a small postsynaptic membrane patch shows characteristic morphological modifications such as greater thickness and higher electron-density, believed to correspond to the transmitter-sensitive receptor site of such synapses. (05 Mar 2000) |
| excitatory postsynaptic potentials | The change in potential produced in the membrane of the next neuron when an impulse which has an excitatory influence arrives at the synapse; it is a local change in the direction of depolarisation; summation of these potentials can lead to discharge of an impulse by the neuron. (12 Dec 1998) |
| action potential | <physiology> The sequential, electrochemical polarization and depolarisation that travels across the membrane of a nerve cell (neuron) in response to stimulation (touch, pain, cold, etc.) (09 Oct 1997) |
| bioelectric potential | Electrical potential's occurring in living organisms. (05 Mar 2000) |
| biological hazard potential | <radiobiology> Measure of the hazard posed by a given quantity of radioactive material in which the variation in biological effects of the various elements are accounted for. See: integrated biological hazard potential. (21 Mar 1998) |
| biotic potential | <biology, ecology> The potential growth a population of living things can expect if it were living under ideal environmental circumstances. (19 Jan 1998) |
| body surface potential mapping | Recording of regional electrophysiological information by analysis of surface potentials to give a complete picture of the effects of the currents from the heart on the body surface. It has been applied to the diagnosis of old inferior myocardial infarction, localization of the bypass pathway in wolff-parkinson-white syndrome, recognition of ventricular hypertrophy, estimation of the size of a myocardial infarct, and the effects of different interventions designed to reduce infarct size. The limiting factor at present is the complexity of the recording and analysis, which requires 100 or more electrodes, sophisticated instrumentation, and dedicated personnel. (12 Dec 1998) |
| brain potential | <physiology> The electrical charge of the brain as compared to a point on the body; the potential may be steady (DC potential) or may fluctuate at specific frequencies when recorded against time, giving rise to the electroencephalogram. (05 Mar 2000) |
| pacemaker potential | The voltage inscribed by impulses from an artificial electronic pacemaker. (05 Mar 2000) |
| generator potential | Local depolarisation of the membrane potential at the end of a sensory neurone in graded response to the strength of a stimulus applied to the associated receptor organ, e.g., a pacinian corpuscle; if the generator potential becomes large enough (because the stimulus is at least of threshold strength), it causes excitation at the nearest node of Ranvier and a propagated action potential. (05 Mar 2000) |
| receptor potential | The transmembrane potential difference of a sensory cell. Such cells are not generally excitable, but their response to stimulation is a gradual change in their resting potential. (18 Nov 1997) |