Review



cx614  (Tocris)


Bioz Verified Symbol Tocris is a verified supplier
Bioz Manufacturer Symbol Tocris manufactures this product  
  • Logo
  • About
  • News
  • Press Release
  • Team
  • Advisors
  • Partners
  • Contact
  • Bioz Stars
  • Bioz vStars
  • 93

    Structured Review

    Tocris cx614
    (A) Experimental schematic (B–D). Pyramidal neurons were whole-cell patched in current (B–D) or voltage clamp (E–J). Current clamp measurements were taken in 1 μM TTX from same cell before and after 5 min incubation with 50 μM PTX. Voltage clamp measurements were taken from different cells with 20 μM <t>CX614</t> or DMSO in extracellular bath. (B) Representative traces (C and D). (C) Membrane resistance is unaltered following mIPSP block with 1 μM TTX and 50 μM PTX (n = 10). (D) Membrane potential is mildly decreased following mIPSP block with 1 μM TTX and 50 μM PTX (n = 9). (E) Scaled average mEPSC event in presence or absence of 20 μM CX614. (F) Representative traces (G–J). (G–J) 20 μM CX614 increases the area (G) and decay time (H), but does not the affect frequency (I) or amplitude (J) of mEPSCs (DMSO, n = 5; CX614, n = 3). (K–P) RNA was collected from cultured hippocampal neurons 6 h after drug treatment. (K and L) Blocking mIPSCs with 1 μM TTX and 50 μM PTX increases Bdnf (K) and Npas4 (L) mRNA, but increasing mEPSC charge transferred with 20 μM CX614 does not (TTX, n = 10; TTX/PTX, n = 10; TTX/CX614, n = 11). (M and N) Blocking mEPSCs with 10 μM CNQX does not alter Bdnf (M) or Npas4 (N) mRNA (TTX, n = 10; TTX/CNQX, n = 8). (O and P) Activating GABA A Rs at rest with 5 μM muscimol decreases Bdnf (O) and Npas4 (P) mRNA (TTX, n = 11; TTX/muscimol, n = 12). Large circles in (C) and (D) are mean ± SEM. Bar graphs are mean + SEM. Open circles next to bars = biological replicates. n.s., non-significant, *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001. See also and .
    Cx614, supplied by Tocris, used in various techniques. Bioz Stars score: 93/100, based on 11 PubMed citations. ZERO BIAS - scores, article reviews, protocol conditions and more
    https://www.bioz.com/result/cx614/product/Tocris
    Average 93 stars, based on 11 article reviews
    cx614 - by Bioz Stars, 2026-05
    93/100 stars

    Images

    1) Product Images from "A subthreshold synaptic mechanism regulating BDNF expression and resting synaptic strength"

    Article Title: A subthreshold synaptic mechanism regulating BDNF expression and resting synaptic strength

    Journal: Cell reports

    doi: 10.1016/j.celrep.2021.109467

    (A) Experimental schematic (B–D). Pyramidal neurons were whole-cell patched in current (B–D) or voltage clamp (E–J). Current clamp measurements were taken in 1 μM TTX from same cell before and after 5 min incubation with 50 μM PTX. Voltage clamp measurements were taken from different cells with 20 μM CX614 or DMSO in extracellular bath. (B) Representative traces (C and D). (C) Membrane resistance is unaltered following mIPSP block with 1 μM TTX and 50 μM PTX (n = 10). (D) Membrane potential is mildly decreased following mIPSP block with 1 μM TTX and 50 μM PTX (n = 9). (E) Scaled average mEPSC event in presence or absence of 20 μM CX614. (F) Representative traces (G–J). (G–J) 20 μM CX614 increases the area (G) and decay time (H), but does not the affect frequency (I) or amplitude (J) of mEPSCs (DMSO, n = 5; CX614, n = 3). (K–P) RNA was collected from cultured hippocampal neurons 6 h after drug treatment. (K and L) Blocking mIPSCs with 1 μM TTX and 50 μM PTX increases Bdnf (K) and Npas4 (L) mRNA, but increasing mEPSC charge transferred with 20 μM CX614 does not (TTX, n = 10; TTX/PTX, n = 10; TTX/CX614, n = 11). (M and N) Blocking mEPSCs with 10 μM CNQX does not alter Bdnf (M) or Npas4 (N) mRNA (TTX, n = 10; TTX/CNQX, n = 8). (O and P) Activating GABA A Rs at rest with 5 μM muscimol decreases Bdnf (O) and Npas4 (P) mRNA (TTX, n = 11; TTX/muscimol, n = 12). Large circles in (C) and (D) are mean ± SEM. Bar graphs are mean + SEM. Open circles next to bars = biological replicates. n.s., non-significant, *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001. See also and .
    Figure Legend Snippet: (A) Experimental schematic (B–D). Pyramidal neurons were whole-cell patched in current (B–D) or voltage clamp (E–J). Current clamp measurements were taken in 1 μM TTX from same cell before and after 5 min incubation with 50 μM PTX. Voltage clamp measurements were taken from different cells with 20 μM CX614 or DMSO in extracellular bath. (B) Representative traces (C and D). (C) Membrane resistance is unaltered following mIPSP block with 1 μM TTX and 50 μM PTX (n = 10). (D) Membrane potential is mildly decreased following mIPSP block with 1 μM TTX and 50 μM PTX (n = 9). (E) Scaled average mEPSC event in presence or absence of 20 μM CX614. (F) Representative traces (G–J). (G–J) 20 μM CX614 increases the area (G) and decay time (H), but does not the affect frequency (I) or amplitude (J) of mEPSCs (DMSO, n = 5; CX614, n = 3). (K–P) RNA was collected from cultured hippocampal neurons 6 h after drug treatment. (K and L) Blocking mIPSCs with 1 μM TTX and 50 μM PTX increases Bdnf (K) and Npas4 (L) mRNA, but increasing mEPSC charge transferred with 20 μM CX614 does not (TTX, n = 10; TTX/PTX, n = 10; TTX/CX614, n = 11). (M and N) Blocking mEPSCs with 10 μM CNQX does not alter Bdnf (M) or Npas4 (N) mRNA (TTX, n = 10; TTX/CNQX, n = 8). (O and P) Activating GABA A Rs at rest with 5 μM muscimol decreases Bdnf (O) and Npas4 (P) mRNA (TTX, n = 11; TTX/muscimol, n = 12). Large circles in (C) and (D) are mean ± SEM. Bar graphs are mean + SEM. Open circles next to bars = biological replicates. n.s., non-significant, *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001. See also and .

    Techniques Used: Incubation, Membrane, Blocking Assay, Cell Culture

    KEY RESOURCES TABLE
    Figure Legend Snippet: KEY RESOURCES TABLE

    Techniques Used: Recombinant, Reverse Transcription, SYBR Green Assay, Sequencing, Plasmid Preparation, Software



    Similar Products

    94
    MedChemExpress cx614
    Cx614, supplied by MedChemExpress, used in various techniques. Bioz Stars score: 94/100, based on 1 PubMed citations. ZERO BIAS - scores, article reviews, protocol conditions and more
    https://www.bioz.com/result/cx614/product/MedChemExpress
    Average 94 stars, based on 1 article reviews
    cx614 - by Bioz Stars, 2026-05
    94/100 stars
      Buy from Supplier

    90
    Cedarlane cx614
    Cx614, supplied by Cedarlane, used in various techniques. Bioz Stars score: 90/100, based on 1 PubMed citations. ZERO BIAS - scores, article reviews, protocol conditions and more
    https://www.bioz.com/result/cx614/product/Cedarlane
    Average 90 stars, based on 1 article reviews
    cx614 - by Bioz Stars, 2026-05
    90/100 stars
      Buy from Supplier

    93
    Tocris cx614
    (A) Experimental schematic (B–D). Pyramidal neurons were whole-cell patched in current (B–D) or voltage clamp (E–J). Current clamp measurements were taken in 1 μM TTX from same cell before and after 5 min incubation with 50 μM PTX. Voltage clamp measurements were taken from different cells with 20 μM <t>CX614</t> or DMSO in extracellular bath. (B) Representative traces (C and D). (C) Membrane resistance is unaltered following mIPSP block with 1 μM TTX and 50 μM PTX (n = 10). (D) Membrane potential is mildly decreased following mIPSP block with 1 μM TTX and 50 μM PTX (n = 9). (E) Scaled average mEPSC event in presence or absence of 20 μM CX614. (F) Representative traces (G–J). (G–J) 20 μM CX614 increases the area (G) and decay time (H), but does not the affect frequency (I) or amplitude (J) of mEPSCs (DMSO, n = 5; CX614, n = 3). (K–P) RNA was collected from cultured hippocampal neurons 6 h after drug treatment. (K and L) Blocking mIPSCs with 1 μM TTX and 50 μM PTX increases Bdnf (K) and Npas4 (L) mRNA, but increasing mEPSC charge transferred with 20 μM CX614 does not (TTX, n = 10; TTX/PTX, n = 10; TTX/CX614, n = 11). (M and N) Blocking mEPSCs with 10 μM CNQX does not alter Bdnf (M) or Npas4 (N) mRNA (TTX, n = 10; TTX/CNQX, n = 8). (O and P) Activating GABA A Rs at rest with 5 μM muscimol decreases Bdnf (O) and Npas4 (P) mRNA (TTX, n = 11; TTX/muscimol, n = 12). Large circles in (C) and (D) are mean ± SEM. Bar graphs are mean + SEM. Open circles next to bars = biological replicates. n.s., non-significant, *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001. See also and .
    Cx614, supplied by Tocris, used in various techniques. Bioz Stars score: 93/100, based on 1 PubMed citations. ZERO BIAS - scores, article reviews, protocol conditions and more
    https://www.bioz.com/result/cx614/product/Tocris
    Average 93 stars, based on 1 article reviews
    cx614 - by Bioz Stars, 2026-05
    93/100 stars
      Buy from Supplier

    90
    Tocris ampakine cx614
    Figure 4. Respiratory depression and respiratory stimulants in larval zebrafish. (A) The respiratory stimulant BIMU8 (10 mM), a 5-HT4A serotonin receptor agonist, in combination with fentanyl (n = 20) was compared to fentanyl alone (n = 4) or BIMU8 alone (n = 21). BIMU8 was not sufficient to reverse respiratory depression by fentanyl. (B) The AMPA positive allosteric modulator <t>CX614</t> (5 mM) and fentanyl (n = 6) were also compared to fentanyl alone (n = 7) or control (n = 7). CX614 + fentanyl group showed significantly higher respiratory rate than fentanyl, DMSO, and control. (C) The analgesic lidocaine (n = 4) was compared to DMSO (0.0016%) (n = 5) and control (n = 5) and showed lower respiratory rate than the control group. Normalized data are presented as means ± standard deviations. Circles indicate individual data points for each zebrafish measured. Black lines and * indicate groups significantly different with p<0.05. Source data can be found in Figure 4—source data 1. The online version of this article includes the following source data for figure 4:
    Ampakine Cx614, supplied by Tocris, used in various techniques. Bioz Stars score: 90/100, based on 1 PubMed citations. ZERO BIAS - scores, article reviews, protocol conditions and more
    https://www.bioz.com/result/ampakine cx614/product/Tocris
    Average 90 stars, based on 1 article reviews
    ampakine cx614 - by Bioz Stars, 2026-05
    90/100 stars
      Buy from Supplier

    90
    Cortex Pharmaceuticals ampakine cx614
    Local field potential recording and analysis during Y-maze exploration. (a)) Behavior testing schedule. Each animal explored the maze for 8 min on each day at P18, 19, 23, and 24. Either <t>CX614</t> (2.5 mg/kg) or vehicle (counterbalanced within animal) was administered 30 min prior to the trial on each testing day. (b) Representative unfiltered local field potential activity during 1 s of maze exploration from one trial, showing location of lowermost electrode in stratum radiatum of hippocampal area CA1. Scale bar is 0.1 ms and 2 mV. (c) Snapshot of video captured during Y-maze exploration. (d) Time-frequency varying power of signal in (b) following convolution with Morlet wavelets and z-scoring. Discrete activity in different wavebands (theta, 4–12 Hz; slow gamma, 25–55 Hz; fast gamma, 65–100 Hz) is apparent. (e) Representative Nissl stained coronal section of an implanted brain showing probe tract terminating in stratum radiatum
    Ampakine Cx614, supplied by Cortex Pharmaceuticals, used in various techniques. Bioz Stars score: 90/100, based on 1 PubMed citations. ZERO BIAS - scores, article reviews, protocol conditions and more
    https://www.bioz.com/result/ampakine cx614/product/Cortex Pharmaceuticals
    Average 90 stars, based on 1 article reviews
    ampakine cx614 - by Bioz Stars, 2026-05
    90/100 stars
      Buy from Supplier

    Image Search Results


    (A) Experimental schematic (B–D). Pyramidal neurons were whole-cell patched in current (B–D) or voltage clamp (E–J). Current clamp measurements were taken in 1 μM TTX from same cell before and after 5 min incubation with 50 μM PTX. Voltage clamp measurements were taken from different cells with 20 μM CX614 or DMSO in extracellular bath. (B) Representative traces (C and D). (C) Membrane resistance is unaltered following mIPSP block with 1 μM TTX and 50 μM PTX (n = 10). (D) Membrane potential is mildly decreased following mIPSP block with 1 μM TTX and 50 μM PTX (n = 9). (E) Scaled average mEPSC event in presence or absence of 20 μM CX614. (F) Representative traces (G–J). (G–J) 20 μM CX614 increases the area (G) and decay time (H), but does not the affect frequency (I) or amplitude (J) of mEPSCs (DMSO, n = 5; CX614, n = 3). (K–P) RNA was collected from cultured hippocampal neurons 6 h after drug treatment. (K and L) Blocking mIPSCs with 1 μM TTX and 50 μM PTX increases Bdnf (K) and Npas4 (L) mRNA, but increasing mEPSC charge transferred with 20 μM CX614 does not (TTX, n = 10; TTX/PTX, n = 10; TTX/CX614, n = 11). (M and N) Blocking mEPSCs with 10 μM CNQX does not alter Bdnf (M) or Npas4 (N) mRNA (TTX, n = 10; TTX/CNQX, n = 8). (O and P) Activating GABA A Rs at rest with 5 μM muscimol decreases Bdnf (O) and Npas4 (P) mRNA (TTX, n = 11; TTX/muscimol, n = 12). Large circles in (C) and (D) are mean ± SEM. Bar graphs are mean + SEM. Open circles next to bars = biological replicates. n.s., non-significant, *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001. See also and .

    Journal: Cell reports

    Article Title: A subthreshold synaptic mechanism regulating BDNF expression and resting synaptic strength

    doi: 10.1016/j.celrep.2021.109467

    Figure Lengend Snippet: (A) Experimental schematic (B–D). Pyramidal neurons were whole-cell patched in current (B–D) or voltage clamp (E–J). Current clamp measurements were taken in 1 μM TTX from same cell before and after 5 min incubation with 50 μM PTX. Voltage clamp measurements were taken from different cells with 20 μM CX614 or DMSO in extracellular bath. (B) Representative traces (C and D). (C) Membrane resistance is unaltered following mIPSP block with 1 μM TTX and 50 μM PTX (n = 10). (D) Membrane potential is mildly decreased following mIPSP block with 1 μM TTX and 50 μM PTX (n = 9). (E) Scaled average mEPSC event in presence or absence of 20 μM CX614. (F) Representative traces (G–J). (G–J) 20 μM CX614 increases the area (G) and decay time (H), but does not the affect frequency (I) or amplitude (J) of mEPSCs (DMSO, n = 5; CX614, n = 3). (K–P) RNA was collected from cultured hippocampal neurons 6 h after drug treatment. (K and L) Blocking mIPSCs with 1 μM TTX and 50 μM PTX increases Bdnf (K) and Npas4 (L) mRNA, but increasing mEPSC charge transferred with 20 μM CX614 does not (TTX, n = 10; TTX/PTX, n = 10; TTX/CX614, n = 11). (M and N) Blocking mEPSCs with 10 μM CNQX does not alter Bdnf (M) or Npas4 (N) mRNA (TTX, n = 10; TTX/CNQX, n = 8). (O and P) Activating GABA A Rs at rest with 5 μM muscimol decreases Bdnf (O) and Npas4 (P) mRNA (TTX, n = 11; TTX/muscimol, n = 12). Large circles in (C) and (D) are mean ± SEM. Bar graphs are mean + SEM. Open circles next to bars = biological replicates. n.s., non-significant, *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001. See also and .

    Article Snippet: CX614 , Tocris , Catalog # 5149.

    Techniques: Incubation, Membrane, Blocking Assay, Cell Culture

    KEY RESOURCES TABLE

    Journal: Cell reports

    Article Title: A subthreshold synaptic mechanism regulating BDNF expression and resting synaptic strength

    doi: 10.1016/j.celrep.2021.109467

    Figure Lengend Snippet: KEY RESOURCES TABLE

    Article Snippet: CX614 , Tocris , Catalog # 5149.

    Techniques: Recombinant, Reverse Transcription, SYBR Green Assay, Sequencing, Plasmid Preparation, Software

    Figure 4. Respiratory depression and respiratory stimulants in larval zebrafish. (A) The respiratory stimulant BIMU8 (10 mM), a 5-HT4A serotonin receptor agonist, in combination with fentanyl (n = 20) was compared to fentanyl alone (n = 4) or BIMU8 alone (n = 21). BIMU8 was not sufficient to reverse respiratory depression by fentanyl. (B) The AMPA positive allosteric modulator CX614 (5 mM) and fentanyl (n = 6) were also compared to fentanyl alone (n = 7) or control (n = 7). CX614 + fentanyl group showed significantly higher respiratory rate than fentanyl, DMSO, and control. (C) The analgesic lidocaine (n = 4) was compared to DMSO (0.0016%) (n = 5) and control (n = 5) and showed lower respiratory rate than the control group. Normalized data are presented as means ± standard deviations. Circles indicate individual data points for each zebrafish measured. Black lines and * indicate groups significantly different with p<0.05. Source data can be found in Figure 4—source data 1. The online version of this article includes the following source data for figure 4:

    Journal: eLife

    Article Title: Respiratory depression and analgesia by opioid drugs in freely behaving larval zebrafish

    doi: 10.7554/elife.63407

    Figure Lengend Snippet: Figure 4. Respiratory depression and respiratory stimulants in larval zebrafish. (A) The respiratory stimulant BIMU8 (10 mM), a 5-HT4A serotonin receptor agonist, in combination with fentanyl (n = 20) was compared to fentanyl alone (n = 4) or BIMU8 alone (n = 21). BIMU8 was not sufficient to reverse respiratory depression by fentanyl. (B) The AMPA positive allosteric modulator CX614 (5 mM) and fentanyl (n = 6) were also compared to fentanyl alone (n = 7) or control (n = 7). CX614 + fentanyl group showed significantly higher respiratory rate than fentanyl, DMSO, and control. (C) The analgesic lidocaine (n = 4) was compared to DMSO (0.0016%) (n = 5) and control (n = 5) and showed lower respiratory rate than the control group. Normalized data are presented as means ± standard deviations. Circles indicate individual data points for each zebrafish measured. Black lines and * indicate groups significantly different with p<0.05. Source data can be found in Figure 4—source data 1. The online version of this article includes the following source data for figure 4:

    Article Snippet: The MOR antagonist CTAP (D-Phe-Cys-Tyr-D-Trp-Arg-Thr-Pen-Thr-NH2), lidocaine, the Ampakine CX614, and the 5-HT4A receptor agonist BIMU8 were obtained from Tocris (ON, Canada).

    Techniques: Control

    Figure 7. Analgesic profiles of larval zebrafish. (A) To determine whether the analgesia assay can be replicated with non-opioid analgesics, we used lidocaine, an analgesic widely used in the clinic. Lidocaine with formalin (n = 19) only moderately reduced swimming velocity compared to formalin alone (n = 10). (B) The respiratory stimulant BIMU8 administered with fentanyl and formalin (n = 17) did not significantly affect swimming velocity when compared to formalin/fentanyl (n = 8). On the other hand, CX614/formalin/fentanyl (n = 12) presented significant differences compared to the control (n = 21). (C) We also looked at the analgesic properties of fentanyl in Tu¨ bingen zebrafish. As observed with the respiratory assays, fentanyl (n = 10) did not reduce the swimming response compared to formalin alone (n = 9) as it did with AB zebrafish. All data are presented as medians with error bars showing 25th and 75th percentile or interquartile range. Circles indicate individual data points for each zebrafish measured. * indicates groups significantly different with p<0.05. Source data can be found in Figure 7—source data 1. The online version of this article includes the following source data and figure supplement(s) for figure 7:

    Journal: eLife

    Article Title: Respiratory depression and analgesia by opioid drugs in freely behaving larval zebrafish

    doi: 10.7554/elife.63407

    Figure Lengend Snippet: Figure 7. Analgesic profiles of larval zebrafish. (A) To determine whether the analgesia assay can be replicated with non-opioid analgesics, we used lidocaine, an analgesic widely used in the clinic. Lidocaine with formalin (n = 19) only moderately reduced swimming velocity compared to formalin alone (n = 10). (B) The respiratory stimulant BIMU8 administered with fentanyl and formalin (n = 17) did not significantly affect swimming velocity when compared to formalin/fentanyl (n = 8). On the other hand, CX614/formalin/fentanyl (n = 12) presented significant differences compared to the control (n = 21). (C) We also looked at the analgesic properties of fentanyl in Tu¨ bingen zebrafish. As observed with the respiratory assays, fentanyl (n = 10) did not reduce the swimming response compared to formalin alone (n = 9) as it did with AB zebrafish. All data are presented as medians with error bars showing 25th and 75th percentile or interquartile range. Circles indicate individual data points for each zebrafish measured. * indicates groups significantly different with p<0.05. Source data can be found in Figure 7—source data 1. The online version of this article includes the following source data and figure supplement(s) for figure 7:

    Article Snippet: The MOR antagonist CTAP (D-Phe-Cys-Tyr-D-Trp-Arg-Thr-Pen-Thr-NH2), lidocaine, the Ampakine CX614, and the 5-HT4A receptor agonist BIMU8 were obtained from Tocris (ON, Canada).

    Techniques: Control

    Local field potential recording and analysis during Y-maze exploration. (a)) Behavior testing schedule. Each animal explored the maze for 8 min on each day at P18, 19, 23, and 24. Either CX614 (2.5 mg/kg) or vehicle (counterbalanced within animal) was administered 30 min prior to the trial on each testing day. (b) Representative unfiltered local field potential activity during 1 s of maze exploration from one trial, showing location of lowermost electrode in stratum radiatum of hippocampal area CA1. Scale bar is 0.1 ms and 2 mV. (c) Snapshot of video captured during Y-maze exploration. (d) Time-frequency varying power of signal in (b) following convolution with Morlet wavelets and z-scoring. Discrete activity in different wavebands (theta, 4–12 Hz; slow gamma, 25–55 Hz; fast gamma, 65–100 Hz) is apparent. (e) Representative Nissl stained coronal section of an implanted brain showing probe tract terminating in stratum radiatum

    Journal: Hippocampus

    Article Title: Hippocampal gamma rhythms during Y-maze navigation in the juvenile rat

    doi: 10.1002/hipo.23168

    Figure Lengend Snippet: Local field potential recording and analysis during Y-maze exploration. (a)) Behavior testing schedule. Each animal explored the maze for 8 min on each day at P18, 19, 23, and 24. Either CX614 (2.5 mg/kg) or vehicle (counterbalanced within animal) was administered 30 min prior to the trial on each testing day. (b) Representative unfiltered local field potential activity during 1 s of maze exploration from one trial, showing location of lowermost electrode in stratum radiatum of hippocampal area CA1. Scale bar is 0.1 ms and 2 mV. (c) Snapshot of video captured during Y-maze exploration. (d) Time-frequency varying power of signal in (b) following convolution with Morlet wavelets and z-scoring. Discrete activity in different wavebands (theta, 4–12 Hz; slow gamma, 25–55 Hz; fast gamma, 65–100 Hz) is apparent. (e) Representative Nissl stained coronal section of an implanted brain showing probe tract terminating in stratum radiatum

    Article Snippet: The AMPAKINE, CX614 (a kind gift from Cortex Pharmaceuticals), was dissolved in (2-hydroxypropyl)-β-cyclodextrin (Sigma-Aldrich) solution (equal parts phosphate-buffered saline (PBS), sterile water, and cyclodextrin powder) immediately prior to use.

    Techniques: Activity Assay, Staining