Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “PLASTICS”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 559 records · Page 31Linked to original sources
PubMed1997

A model of long-term memory storage in the cerebellar cortex: a possible role for plasticity at parallel fiber synapses onto stellate/basket interneurons.

By evoking changes in climbing fiber activity, movement errors are thought to modify synapses from parallel fibers onto Purkinje cells (pf*Pkj) so as to improve subsequent motor performance. Theoretical arguments suggest there is an intrinsic tradeoff, however, between motor adaptation and long-term storage. Assuming a baseline rate of motor errors is always present, then repeated performance of any learned movement will generate a series of climbing fiber-mediated corrections. By reshuffling the synaptic weights responsible for any given movement, such corrections will degrade the memories for other learned movements stored in overlapping sets of synapses. The present paper shows that long-term storage can be accomplished by a second site of plasticity at synapses from parallel fibers onto stellate/basket interneurons (pf*St/Bk). Plasticity at pf*St/Bk synapses can be insulated from ongoing fluctuations in climbing fiber activity by assuming that changes in pf*St/Bk synapses occur only after changes in pf*Pkj synapses have built up to a threshold level. Although climbing fiber-dependent plasticity at pf*Pkj synapses allows for the exploration of novel motor strategies in response to changing environmental conditions, plasticity at pf*St/Bk synapses transfers successful strategies to stable long-term storage. To quantify this hypothesis, both sites of plasticity are incorporated into a dynamical model of the cerebellar cortex and its interactions with the inferior olive. When used to simulate idealized motor conditioning trials, the model predicts that plasticity develops first at pf*Pkj synapses, but with additional training is transferred to pf*St/Bk synapses for long-term storage.

Animals↗
PubMed1999

Patch-test reactions to plastic and glue allergens.

Plastics and glues are common causes of occupational dermatoses, but only few reports have dealt with patch-test reactions caused by plastic and glue allergens. Patients exposed to plastics and remitted to an occupational dermatology clinic, were patch-tested with 50-53 plastic and glue allergens during a 6-year period. Conventional patch-test techniques were used. The most common causes of allergic patch-test reactions in 360 patients were novolac epoxy resin (5.1%), phenol formaldehyde resin (3.1%), 4-tert-butylcatechol (2.6%), phenyl glycidyl ether (2.6%), diaminodiphenyl methane (2.2%), benzoyl peroxide (2.2%), hexamethylene tetramine (2.0%) and o-cresyl glycidyl ether (1.6%). The allergens that most often elicited irritant patch-test reactions were: benzoyl peroxide (9.5%), abitol alcohol (3.6%), hydroquinone (3.1%), acid-catalyzed phenol formaldehyde resin (2.5%) and toluene diisocyanate (1.9%). Twenty-six out of 53 chemicals caused no allergic reaction during the 6-year period. Plastic allergens in the standard series provoked allergic reactions with formaldehyde (5.8%), diglycidyl ether of bisphenol A (3.2%), 4-tert-butylphenol-formaldehyde-resin (1.1%), toluene sulphonamide formaldehyde-resin (1.1%) and triethylenglycol diacrylate (0.4%). Although half of the plastic chemicals gave no allergic patch-test reactions during a 6-year period, with unusual allergens this low yield needs to be accepted, because otherwise rare allergies will not be detected. Also a negative reaction has diagnostic value.

Acrylic Resins↗
PubMedDate not supplied

Migration of plasticizers from printing inks into foods.

It has been demonstrated that on storage of a tightly wound reel of polypropylene packaging film, specially printed for experimental purposes, transfer can occur of components from the ink on the outer surface of the film on to the inner food contact surface. For dicyclohexyl phthalate this transfer amounted to 6% of the total amount of plasticizer available in the printing ink system. It was subsequently shown for confectionery and snack food products wrapped in commercially printed polypropylene films that plasticizers only present in the printing ink migrated into the foods. The migration of plasticizer increased with storage time of the wrapped product; for dibutyl phthalate, for example, levels increased from 0.2 to 6.7 mg/kg over the period from 0 to 180 days storage of a chocolate-coated confectionery product. A small retail survey (47 samples) of confectionery, snack products and biscuits wrapped in printed polypropylene film showed the presence of one or more plasticizers at levels from 0.02 to 14.1 mg/kg for dibutyl phthalate, from less than 0.01 to 18.6 mg/kg for dicyclohexyl phthalate and from less than 0.01 to 1.8 mg/kg for di(2-ethylhexyl) phthalate. In all cases there was a good correlation between the plasticizers found in the printing ink from the film and those in the food. Wide variations were found, however, in the amounts and types of plasticizers used in printed packaging of the same brand of retail food product purchased from different regions of the country.

Food Contamination↗
PubMedDate not supplied

The effect of microwave energy on specific migration from food contact plastics.

Experiments have been carried out with (a) microwave treatment of plastics followed by migration testing using the food simulant, olive oil, and (b) microwave treatment of plastics in direct contact with an organic extractant (iso-octane). In neither of these complementary approaches was there evidence of any difference in migration from plastics that had been microwave-treated compared with plastics that had received an equivalent thermal treatment. Five plastics commonly employed in microwave applications were tested and oligomers, plasticizer, antioxidant and volatile contaminants were monitored as representatives of typical migration species.

Dietary Fats, Unsaturated↗
PubMed2007

Cognitive plasticity in people at risk for dementia: optimising the testing-the-limits-approach.

A topic of great interest in gerontology research is the prediction of cognitive deterioration which marks the transition from mild cognitive impairment (MCI) to dementia. In this area, the term cognitive plasticity can be of great interest. We examined the utility of the Adaptive Figure Series Learning Test (ADAFI) to evoke cognitive plasticity and to show whether reduced plasticity can be found in people with MCI. In a pre-test-intervention-post-test design, intervention with the ADAFI was compared to an unspecific brain jogging task in MCI participants and healthy controls. A total of 42 subjects were included. Independent of mental health status only using the ADAFI led to pronounced improvements in post-test performances, but MCI participants profited less from the intervention with the ADAFI than healthy controls, that is, showed lower cognitive plasticity. Thus, the overlap in performance distributions between healthy participants and MCI individuals at pre-test was reduced at the time of post-test once the ADAFI had been given as intervention. The findings of the present article indicate that plasticity oriented information can be gained when the ADAFI is given as an intervention in a pre-test-training-post-test-design. The cognitive plasticity approach seems potentially useful for purposes of early identification of dementia.

Aged↗
PubMed2003

Development of floating plastic media filtration system for water treatment and wastewater reuse.

Floating plastic media coupled with sand filtration system was applied for treating surface water and secondary effluent from municipal sewage treatment plant. The system employed floating plastic media for the removal of suspended solids in surface water and precipitated phosphorus from secondary effluent of sewage treatment plant. Sand filtration was then used to remove further the suspended solids. For the purposes of wastewater reuse, a zeolite layer was used instead of sand filter to absorb ammonium nitrogen. Application of system for surface water treatment suggested appropriate filtration rate of 5 m3/m2 h. Polyaluminum chloride was found to be the best coagulant with an appropriate plastic and sand bed depth of 40 cm. The system could produce average effluent turbidity and suspended solids of 0.71 NTU and 0.94 mg/L respectively. Average turbidity and suspended solids removal efficiencies were 96.26% and 95.48% with low headloss development of 40.4 cm at the end of 6 h operation period. When applying 1.50 m. floating plastic media bed for the treatment of synthetic raw water, short and long-term turbidity removal efficiencies were 96.79-97.72% and 81.81-94.61% for raw water containing turbidity of 20 and 40 NTU. It could produce the effluent with turbidity less than 5NTU while having less than 1.0 m. headloss. The system was also applied for the secondary effluent treatment. An optimum filtration rate of 5 m3/m2 h was obtained when using plastic and sand bed depth of 60 and 20cm under direct filtration mode. Average turbidity removal was 60.3% and 59.6% after 6 and 48 h of operation. It was also found that 1 m3/m2 h filtration rate and 50:30 cm of plastic:zeolite bed could be used to achieve both ammonium nitrogen and phosphate removal. Suspended solids, turbidity, BOD5, NH4+, and PO4(3-) removal efficiencies were 91.9, 94.6, 95.4, 97.3, and 99.5% respectively after 24 h. As a result, the effluent from the system had average NH4+ and PO4(3-) of 0.5 mg N/L and 0.02 mg P/L.

Absorption↗
PubMed2002

Fluence correction factors in plastic phantoms for clinical proton beams.

In recent codes of practice for reference dosimetry in clinical proton beams using ionization chambers, it is recommended to perform the measurement in a water phantom. However, in situations where the positioning accuracy is very critical, it could be more convenient to perform the measurement in a plastic phantom. In proton beams, a similar approach as in electron beams could be applied by introducing fluence correction factors in order to account for the differences in particle fluence distributions at equivalent depths in plastic and water. In this work, fluence correction factors as a function of depth were determined for proton beams with different energies using the Monte Carlo code PTRAN for PMMA and polystyrene with reference to water. The influence of non-elastic nuclear interaction cross sections was investigated. It was found that differences in proton fluence distributions are almost entirely due to differences in non-elastic nuclear interaction cross sections between the plastic materials and water. For proton beams with energies lower than 100 MeV, for which the contributions from non-elastic interactions become small compared to the total dose, the fluence corrections are smaller than 1%. For beams with energies above 200 MeV, depending on the cross sections dataset for non-elastic nuclear interactions, fluence corrections of 2-5% were found at the largest depths. The results could, with an acceptable accuracy, be represented as a correction per cm penetration of the beam, yielding values between 0.06% and 0.15% per cm for PMMA and 0.06% to 0.20% per cm for polystyrene. Experimental information on these correction factors was obtained from depth dose measurements in PMMA and water. The experiments were performed in 75 MeV and 191 MeV non-modulated and range-modulated proton beams. From the experiments, values ranging from 0.03% to 0.15% per cm were obtained. A decisive answer about which dataset for non-elastic nuclear interactions would result in a better representation of the measurements could not be given. We conclude that below 100 MeV, dosimetry could be performed in plastic phantoms without a dramatic loss of accuracy. On the other hand, in clinical high-energy proton beams, where accurate positioning in water is in general not an issue, substantial correction factors would be required for converting dose measurements in a plastic phantom to absorbed dose to water. It is therefore not advisable to perform absorbed dose measurements nor to measure depth dose distributions in a plastic phantom in high-energy proton beams.

Calibration↗
PubMed2003

Roles of protein kinase A and protein kinase G in synaptic plasticity in the visual cortex.

Monocular deprivation leads to clear physiological and anatomical changes in the visual cortex known as ocular dominance plasticity. Protein kinase A (PKA) is necessary for ocular dominance plasticity, while protein kinase G (PKG) is not. We have now tested the role of PKA and PKG in long-term potentiation (LTP) and long-term depression (LTD). We have shown that PKA inhibitors have a major effect on both LTP and LTD in the visual cortical slices, whereas a PKG inhibitor affects LTP but not LTD. The PKA activator, 8-chloroadenosine-3',5'-monophosphorothioate, Sp-isomer (Sp-8-Cl-cAMPS), by itself induces a slowly rising form of LTP, which is occluded by theta-burst stimulation (TBS)-induced LTP. These results support the point that the PKA signaling pathway is crucial for neuronal plasticity in visual cortex, and the dissociation of the role of PKA and PKG in long-term synaptic plasticity in the visual cortex suggests that LTP alone is not sufficient to support ocular dominance plasticity, or LTD plays a more fundamental role than LTP in ocular dominance plasticity.

Animals↗
PubMed2001

An approach to enhance the interface adhesion between an orthodontic plastic bracket and adhesive.

For the purpose of improving the degree of success of plastic bracket bonding, based on the analysis of the chemical components of plastic brackets, a systematic method for the treatment of the adhesive surface of plastic brackets was introduced in this study. After sandblasting the adhesive surfaces of two commercially available plastic brackets (Spirit and Clear Bracket), a favourable surface treatment was obtained with the application of a silane coupling agent, gamma-methacryloxy propyl trimethoxy silane. The findings showed that (i) the fillers added to the plastic brackets were glass fillers with Si-OH groups distributed on their surfaces; (ii) sandblasting of the bracket surface resulted in exposure of the glass fillers; (iii) combined with sandblasting, silane coupling treatment significantly increased the bond strength (P < 0.05), which was adequate to withstand the forces generated during orthodontic therapy; and (iv) treatment with sandblasting and silane coupling 24 hours before direct bonding did not cause a significant reduction in bond strength. It is concluded that sandblasting and silane coupling treatment offers the benefit of increasing the in vitro bond strength of plastic brackets for orthodontic application.

Adhesiveness↗
PubMed1999

Vilray P. Blair, his surgical descendants, and their roles in plastic surgical development.

Perhaps one of the most historically well-known plastic surgeons is Vilray P. Blair. As commander of the U.S. Army corps of head and neck surgeons during World War I, he became well known for his work in posttraumatic reconstruction. Blair's efforts in the early part of this century helped to develop plastic surgery as a distinct surgical subspecialty in the United States. His prowess as a surgeon allowed him to build one of the largest plastic surgery centers in the country and to train many of the top young American surgeons. Blair excelled as a teacher. He produced academic surgeons such as James Barrett Brown and Bradford Cannon, who took the lead in the care of wartime injuries during World War II. At Valley Forge General Hospital, Blair's trainees dedicated themselves to the reconstruction of injured patients and trained other young plastic surgeons in the care of postwar trauma. This exceptional level of patient care resulted in the U.S. government recognizing plastic surgery as a subspecialty following World War II. Since that time, Blair's surgical descendants at Washington University have led the country in the development of new training concepts and ideals and have gone on to become leaders in plastic surgery worldwide.

History, 19th Century↗
PubMed1999

The financial environment of aesthetic surgery: results of a survey of plastic surgeons.

To gather information about aesthetic surgery's current practice structures, competitive environment, patient price sensitivity, and marketing and practice development requirements, a two-page survey was developed and mailed to all 1180 members of the American Society for Aesthetic Plastic Surgery. A total of 632 surveys were returned (response rate of 54.5 percent). Most aesthetic plastic surgeons said they were in solo practice (63.3 percent). More than two-thirds described the marketplace as "very competitive," with 59 percent reporting 25 or more surgeons offering aesthetic surgery in their area. They estimated their patients' average income at $62,800. Nearly all plastic surgeons labeled their patients as "moderately price sensitive" (62.3 percent) or "very price sensitive" (30.6 percent). Similarly, 23.2 percent estimated that they had lost 20 or more patients within the last year for reasons of price. Practice development and marketing efforts represented an average of 7.3 percent of plastic surgeons' working time. Parameters associated with a high percentage of time devoted to these activities were solo practice, percentage of revenue from aesthetic surgery greater than 50 percent, a practice environment designation of moderately or very competitive, and ten or more area surgeons offering aesthetic surgery (p < 0.05). High patient income led to only slight decreases in price sensitivity and did not significantly reduce the amount of time spent on marketing and practice development. Although the rest of the healthcare industry has undergone a period of consolidation, aesthetic surgeons have been able to resist these changes. The results of this survey suggest that the fragmented nature of the aesthetic surgery industry is associated with additional burdens on plastic surgeons. As the aesthetic surgery market becomes more competitive, plastic surgeons may benefit from consolidation to reduce costs and maximize efficiency.

Fees and Charges↗
PubMed2003

Safety and efficacy of office-based surgery with monitored anesthesia care/sedation in 4778 consecutive plastic surgery procedures.

Office-based surgery has several potential benefits over hospital-based surgery, including cost containment, ease of scheduling, and convenience to both patients and surgeons. Scrutiny of office-based surgery by regulators and state-licensing agencies has increased and must be addressed by improved documentation of safety and efficacy. To evaluate the safety and efficacy of the authors' office-based plastic surgery, a review was undertaken of 3615 consecutive patients undergoing 4778 outpatient plastic surgery procedures under monitored anesthesia care/sedation in a single office. The charts of 3615 consecutive patients who had undergone office-based surgery with monitored anesthesia care/sedation between May of 1995 and May of 2000 were reviewed. In all cases, the anesthesia protocol used included sedation with midazolam, propofol, and a narcotic administered by a board-certified registered nurse anesthetist with local anesthesia provided by the surgeon. Charts were reviewed for patient profile, types of procedures, multiple procedures, duration of anesthesia, American Society of Anesthesiologists class, and complications related to anesthesia. Outcomes measured included death, airway compromise, dyspnea, hypotension, venous thrombosis, pulmonary emboli, protracted nausea and vomiting lasting more than 24 hours, and unplanned hospital admissions. Statistical analyses were performed using the Microsoft Excel program and the SAS package. Results were as follows: 92.3 percent of the patients were female and 7.7 percent were male, with a mean age of 42.7 years (range, 3 to 83 years). Patients underwent aesthetic (95.6 percent) and reconstructive (4.4 percent) plastic surgery procedures. Same-session multiple procedures occurred in 24.8 percent of patients. The vast majority of patients were healthy: 84.3 percent of patients were American Society of Anesthesiologists class I, 15.6 percent were class II, and 0.1 percent were class III. The operations required a mean of 111 minutes. There were no deaths, ventilator requirements, deep venous thromboses, or pulmonary emboli. Complications were as follows: 0.05 percent (n = 2) of patients had dyspnea that resolved, 0.2 percent (n = 6) of patients had protracted nausea and vomiting, and 0.05 percent (n = 2) of patients had unplanned hospital admissions (<24 hours). One patient had an emergent intubation. No prolonged adverse effects were noted. There was a 30-day follow-up minimum. Outpatient surgery is an important aspect of plastic surgery. It was shown that office-based surgery with intravenous sedation, performed by board-certified plastic surgeons and nurse anesthetists, is safe. Appropriate accreditation, safe anesthesia protocols, and proper patient selection constitute the basis for safe and efficacious office-based outpatient plastic surgery.

Adolescent↗
PubMed2003

Factors determining the ultimate fate of a plastic surgery applicant.

Plastic surgery residency program directors are frequently interested in predictors of future career direction in their applicants. Many programs strive to train leaders in academic plastic surgery. To determine what factors may predict the ultimate fate of graduating plastic surgery residents, the authors reviewed the application files of 33 former residents from a single, major plastic surgery training program. The data from 29 residents were available for analysis. Nearly half of the residents graduating from the plastic surgery training program went into private practice. Two factors, the number of years taken off for research before entering the plastic surgery residency and the presence of children, were found to be indicative of a candidate's future career path. Of particular note, there was no difference between academic graduates and nonacademic graduates with regard to their intentions in their letters of recommendation and personal statements. This information is useful to both academic program directors and resident applicants.

Female↗
PubMed2003

Differences in breast shape preferences between plastic surgeons and patients seeking breast augmentation.

There has been little discussion in the published literature regarding breast shape preferences. This study was conducted to ascertain previously undocumented differences in breast shape preferences between plastic surgeons and patients seeking breast augmentation, with respect to upper-pole contour. Sixty-six respondents, grouped into three cohort categories (plastic surgeons, breast augmentation patients, and lay people), were asked to evaluate a series of 12 nonptotic breast profiles representing a range of upper-pole contours. Five profiles exhibited convex upper-pole contours, five exhibited concave contours, and two exhibited upper poles with flat slopes. A five-point Likert-type scale was used to rate attractiveness, naturalness, how close the shape was to each respondent's personal ideal, and how close the shape was to what the respondent believed was our society's ideal. Statistical comparisons were made among the three cohorts. The plastic surgeon cohort (n = 11) rated concave upper-pole contours significantly higher than did the patient cohort (n = 13) for attractiveness, naturalness, and personal ideal (p < 0.01). For convex contours, the plastic surgeon cohort gave significantly lower scores than did the patient cohort (p < 0.01). The lay category (n = 42) demonstrated preferences intermediate between those of the other groups. There are no known studies in the literature documenting the breast shape preferences of plastic surgeons and their patients. This study suggests that plastic surgeons and patients seeking breast augmentation may have drastically different images in mind regarding what constitutes an attractive, natural, and ideal breast shape. These findings have potential implications for patient treatment and satisfaction.

Adult↗
PubMed1993

Role of fibronectin in staphylococcal colonisation of fibrin thrombi and plastic surfaces.

The adhesive glycoprotein fibronectin has been proposed as a mediator of adherence of certain gram-positive cocci to host cells and fibrin thrombi. This study compared the role of soluble and immobilised fibronectin in the adherence of coagulase-negative staphylococci (CNS) and Staphylococcus aureus to fibrin thrombi and plastic surfaces. Adherence of S. epidermidis to fibrin thrombi was significantly reduced when fibronectin was removed from the plasma used for thrombus preparation. Adherence was restored through restitution of fibronectin. S. epidermidis also adhered substantially more to plastic surface coated with fibronectin than to non-coated plastic. Increased adherence of CNS to plastic was also observed after coating with the 29-kDa N-terminal fragment of fibronectin. Soluble fibronectin did not affect the adherence of CNS to fibrin thrombi or plastic surfaces. The adherence of S. aureus to fibrin thrombi was significantly increased by the addition of soluble fibronectin, but not by incorporation of fibronectin into the clot. These results indicate that the binding of fibronectin is an important factor in the adherence of staphylococci to fibrin clots and plastic surfaces and, thus, colonisation of these surfaces. However, the two species of staphylococci seem to employ different mechanisms of fibronectin-mediated adherence: S. epidermidis interacts mainly with fibronectin incorporated in fibrin clots or immobilised on implanted synthetic materials, whereas S. aureus adheres to the fibrin matrix through binding of soluble fibronectin present in wound exudates.

Albumins↗
PubMed2006

Age-dependent glutamate induction of synaptic plasticity in cultured hippocampal neurons.

A common denominator for the induction of morphological and functional plasticity in cultured hippocampal neurons involves the activation of excitatory synapses. We now demonstrate massive morphological plasticity in mature cultured hippocampal neurons caused by a brief exposure to glutamate. This plasticity involves a slow, 70%-80% increase in spine cross-section area associated with a significant reduction in the width of dendrites. These changes are age dependent and expressed only in cells >18 d in vitro (DIV). Activation of both NMDARs and AMPARs as well as a sustained rise of internal calcium levels are necessary for induction of this plasticity. On the other hand, blockade of network activity or mGluRs does not abolish the observed morphological plasticity. Electrophysiologically, a brief exposure to glutamate induces an increase in the magnitude of EPSCs evoked between pairs of neurons, as well as in mEPSC frequency and amplitude, in mature but not young cultures. These results demonstrate an age-dependent, rapid and robust morphological and functional change in cultured central neurons that may contribute to their ability to express long term synaptic plasticity.

Adaptation, Physiological↗
PubMedDate not supplied

Long-term plasticity of intrinsic excitability: learning rules and mechanisms.

Spatio-temporal configurations of distributed activity in the brain is thought to contribute to the coding of neuronal information and synaptic contacts between nerve cells could play a central role in the formation of privileged pathways of activity. Synaptic plasticity is not the exclusive mode of regulation of information processing in the brain, and persistent regulations of ionic conductances in some specialized neuronal areas such as the dendrites, the cell body, and the axon could also modulate, in the long-term, the propagation of neuronal information. Persistent changes in intrinsic excitability have been reported in several brain areas in which activity is elevated during a classical conditioning. The role of synaptic activity seems to be a determinant in the induction, but the learning rules and the underlying mechanisms remain to be defined. We discuss here the role of synaptic activity in the induction of intrinsic plasticity in cortical, hippocampal, and cerebellar neurons. Activation of glutamate receptors initiates a long-term modification in neuronal excitability that may represent a parallel, synergistic substrate for learning and memory. Similar to synaptic plasticity, long-lasting intrinsic plasticity appears to be bidirectional and to express a certain level of input or cell specificity. These nonsynaptic forms of plasticity affect the signal propagation in the axon, the dendrites, and the soma. They not only share common learning rules and induction pathways with the better-known synaptic plasticity such as NMDA receptor dependent LTP and LTD, but also contribute in synergy with these synaptic changes to the formation of a coherent engram.

Action Potentials↗
PubMed2005

Role of the glycine site of the N-methyl-D-aspartate receptor in synaptic plasticity induced by pairing.

In the hippocampal CA1 region of the rat, activity-dependent plasticity requires substantial postsynaptic depolarization and activation of the N-methyl-D-aspartate glutamate receptor subtype (NMDAR). Exogenous and endogenous compounds selectively modulate NMDAR function by acting at the glycine coagonist site. Here we investigate the modulatory role of the glycine site in the induction of bidirectional synaptic plasticity. Plasticity was induced by pairing low-frequency afferent pulses with different levels of postsynaptic depolarization in the absence and presence of glycine site compounds. We found strong dependence of glycine site agonist modulation on membrane voltage during induction. Thus, D-serine and glycine were more effective in enhancing long-term potentiation (LTP) during pairing of small depolarization (-60 or -50 mV) with subthreshold EPSCs than during pairing of stronger depolarization (-40 mV) with suprathreshold synaptic responses. The glycine site role in bidirectional synaptic plasticity was studied with the selective antagonist 7-chlorokynurenic acid. Blockade of the glycine site during the pairing reversed the direction of plasticity from LTP towards long-term depression. The magnitude of depression was dependent on antagonist concentration and the level of depolarization during the pairing. Thus, these experiments demonstrate the role of the glycine site in the induction of bidirectional synaptic plasticity.

Afferent Pathways↗