scholarly journals Time course of transient behavioral depression and persistent behavioral sensitization in relation to regional brain monoamine concentrations during amphetamine withdrawal in rats

1991 ◽  
Vol 103 (4) ◽  
pp. 480-492 ◽  
Author(s):  
Pamela E. Paulson ◽  
Dianne M. Camp ◽  
Terry E. Robinson
Keyword(s):  
Time Course ◽  
Behavioral Sensitization ◽  
Behavioral Depression ◽  
Regional Brain ◽  
Amphetamine Withdrawal ◽  
Brain Monoamine

P.6.d.016 Distinct time-course of behavioral sensitization induced by ethanol or cocaine

2008 ◽  
Vol 18 ◽  
pp. S548
Author(s):  
A.J. Oliveira-Lima ◽  
E.A.V. Marinho ◽  
R. Wuo-Silva ◽  
R. Santos ◽  
M.A. Baldaia ◽  
...  
Keyword(s):  
Time Course ◽  
Behavioral Sensitization

Pharmacological and kinetic characterization of two functional classes of serotonergic modulation in Aplysia sensory neurons

1996 ◽  
Vol 75 (2) ◽  
pp. 855-866 ◽  
Author(s):  
L. L. Stark ◽  
A. R. Mercer ◽  
N. J. Emptage ◽  
T. J. Carew
Keyword(s):  
Synaptic Transmission ◽  
Sensory Neurons ◽  
Time Course ◽  
Behavioral Sensitization ◽  
Input Resistance ◽  
Short Term ◽  
Synaptic Facilitation ◽  
Functional Classes ◽  
Kinetics Of ◽  
Serotonergic Modulation

1. Modulation of mechanoafferent sensory neurons (SNs) by the neutrotransmitter serotonin (5HT) plays a significant role in behavioral sensitization of several withdrawal reflexes in Aplysia. The modulatory effects of 5HT on these SNs include increased excitability, increased input resistance, action potential broadening, and increased synaptic transmission. Based on a previously described dissociation of some of these modulatory effects, revealed with the 5HT-receptor antagonist, cyproheptadine, we investigated whether a similar dissociation could be found by systematically varying the concentration of the endogenous agonist, 5HT. 2. We first applied a range of 5HT concentrations to isolated pleural/pedal ganglia (containing tail SNs and tail motor neurons, respectively), and measured the magnitude of 5HT-induced modulation of spike broadening and increased excitability. The resulting dose-response curve showed that both forms of modulation increase monotonically as a function of 5HT concentration, but that excitability has a lower threshold for modulation by 5HT than does spike duration. 3. We further characterized the modulatory effects of 5HT on Aplysia SNs by comparing the time course of onset of modulation by 5HT and the time course of recovery after washout. Independent of 5HT concentration, modulation of excitability increases rapidly in the presence of 5HT and recovers rapidly (< 3 min) after washout. Similarly, input resistance increases and recovers rapidly, mirroring the profile of increased excitability. However, modulation of spike duration exhibits two profiles, dependent on 5HT concentration. Low concentrations of 5HT (0.5 and 1 microM) induce a rapid-onset and transient-recovery form of spike broadening, which resembles the kinetics of increased excitability and increased input resistance. Higher concentrations of 5HT (2.5 and 5 microM) induce a more slowly developing and prolonged-recovery form of spike broadening (> 9 min). At these higher concentrations, the recovery profile for prolonged spike broadening is significantly different from those observed for both increased excitability and increased input resistance. 4. We next compared the relationship between spike broadening and short-term synaptic facilitation. We found that significant facilitation of synaptic transmission requires a high 5HT concentration, which is comparable with that required to induce prolonged spike broadening. Similarly, the recovery profiles for spike broadening and synaptic facilitation are strikingly similar, recovering in parallel. 5. Our experiments show that the modulatory effects of 5HT in the tail SNs can be dissociated both by their sensitivity to different concentrations of 5HT and by their kinetics of serotonergic modulation. Based on these results, together with extensive evidence from other laboratories, we propose that the short-term modulatory effects of 5HT fall into two distinct functional classes. The first class, which includes excitability, input resistance, and transient spike broadening, has a low threshold for 5HT modulation and recovers rapidly. The second class, which includes prolonged spike broadening and short-term synaptic facilitation, has a higher threshold for modulation and recovers more slowly. It now will be of interest to determine the functional contribution of each of these classes to different aspects of sensitization.

scholarly journals Tracking tau fibrillogenesis and consequent primary phagocytosis of neurons mediated by microglia in a living tauopathy model

2020 ◽  
Author(s):  
Hiroyuki Takuwa ◽  
Asumi Orihara ◽  
Yuhei Takado ◽  
Takuya Urushihata ◽  
Masafumi Shimojo ◽  
...  
Keyword(s):  
Neuronal Death ◽  
Time Course ◽  
Translocator Protein ◽  
Two Photon ◽  
Regional Brain ◽  
Laser Optics ◽  
Continuous Generation ◽  
Regional Brain Atrophy ◽  
Phagocytotic Activity ◽  
Partial Depletion

ABSTRACTFibrillary tau pathologies have been implicated in Alzheimer’s and allied neurodegenerative diseases, while mechanisms by which neurons bearing tau tangles die remain enigmatic. To address this issue, we pursued tau and related key pathologies macroscopically by PET and MRI and microscopically by intravital two-photon laser optics. Time-course macroscopic assays of tau transgenic mice demonstrated intimate associations of tau deposition and increase of an inflammatory microglial marker, translocator protein (TSPO), with regional brain atrophy. Longitudinal microscopy of these mice revealed a rapid turnover of tau lesions resulting from continuous generation of new tau aggregates followed by loss of neurons and their fibrillar contents. This technology also allowed the capturing of the disappearance of tangle-bearing neurons several days after being engulfed by activated microglia. Notably, a therapeutic TSPO ligand profoundly suppressed the mobility and phagocytotic activity of microglia and improved neuronal survival in this model, supporting the involvement of primary phagocytosis of viable neurons by microglia in tau-primed neuronal death. Finally, partial depletion of microglia revealed roles of immune factors, MFG-E8 and C1q, as ‘eat-me’ signals for an immediate attraction of phagocytic microglia towards the elimination of tangle-loaded neurons.

scholarly journals Tyrosine Uptake and Regional Brain Monoamine Metabolites in a Rat Model Resembling Congenital Hyperammonemia

1996 ◽  
Vol 39 (6) ◽  
pp. 1036-1040 ◽  
Author(s):  
Jean-Pierre Colombo ◽  
Claude Bachmann ◽  
Heidi Cervantes ◽  
Milica Kokorovic ◽  
Rachel Perritaz
Keyword(s):  
Rat Model ◽  
Monoamine Metabolites ◽  
Regional Brain ◽  
Tyrosine Uptake ◽  
Brain Monoamine

Caffeine and regional brain monoamine utilization in mice

Life Sciences ◽  
1989 ◽  
Vol 45 (26) ◽  
pp. 2637-2644 ◽  
Author(s):  
M.G. Hadfield ◽  
C. Milio
Keyword(s):  
Regional Brain ◽  
Brain Monoamine

Regional brain monoamine levels and utilization in middle-aged rats

Life Sciences ◽  
1990 ◽  
Vol 46 (4) ◽  
pp. 295-299 ◽  
Author(s):  
M.G. Hadfield ◽  
C. Milio
Keyword(s):  
Aged Rats ◽  
Middle Aged ◽  
Regional Brain ◽  
Brain Monoamine
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