Journal: Journal of Neurochemistry

Article Title: Preserving Neuronal Chemical Messengers: Heat Stabilization Versus Snap Freezing for Improved MALDI Mass Spectrometry Imaging of Brain Tissues

doi: 10.1111/jnc.70122

Figure Lengend Snippet: MALDI‐MS images of neurotransmitters and related metabolites acquired from FF and HS tissue sections. (a) DA, double derivatized, (b) NE, double derivatized, (c) DOPAL, double derivatized, (d) DOPAC, double derivatized, (e) HVA, single derivatized, (f) 3‐MT, single derivatized, (g) MOPAL, single derivatized, (h) DOPEG, double derivatized, (i) 5‐HT, single derivatized, (j) 5‐HIAA, single derivatized, (k) 5‐HIAL, single derivatized, (l) GABA, single derivatized. (a, c‐g), coronal rat brain section at bregma 2.28 mm, and (b, h–l), coronal rat brain section at bregma −2.04 mm. Scale bar, 2 mm. Color scale bars are shown as percentage of maximum intensity. (m) Box plots reflecting normalized average intensity of DA, DOPAL, DOPAC, HVA, 3‐MT, and MOPAL in caudate‐putamen (CPu) at bregma 2.28 mm, and NE, DOPEG, 5‐HT, 5‐HIAA, 5‐HIAL, and GABA in hypothalamus (Hypo) at bregma −2.04 mm of HS and FF brain sections ( n = 4). Statistical comparison of DA, NE, 5‐HT, and their metabolites between HS and FF protocols is presented in Table . Lateral resolution, 150 μm. Data were normalized against IS, that is, DA‐ d 4 for DA, DOPAL, DOPAC, 3‐MT, MOPAL, 5‐HT, NE, DOPEG, 5‐HIAL, and 5‐HIAA, HVA‐ d 5 for HVA, and GABA‐ d 6 for GABA. The annotation of the brain regions is represented in Figure . 3‐MT, 3‐methoxytyramine; 5‐HIAA, 5‐hydroxyindoleacetic acid; 5‐HIAL, 5‐hydroxyindoleacetaldehyde; 5‐HT, serotonin; CPu, caudate‐putamen; Hypo, hypothalamus; DA, dopamine; DOPAC, 3,4‐dihydroxyphenylacetic acid; DOPAL, 3,4‐dihydroxyphenylacetaldehyde; DOPEG, 3,4‐dihydroxyphenylglycol; GABA, γ‐aminobutyric acid; HVA, homovanillic acid; MOPAL, 3‐methoxy‐4‐hydroxyphenylacetaldehyde; NE, norepinephrine. The p ‐values were obtained using a parametric, two‐tailed Student's t‐test for independent groups ( n =4). * p ≤ 0.05, ** p ≤ 0.01.

Article Snippet: Isotope‐labeled neurotransmitters (dopamine‐1,1,2,2‐ d 4 • HCl (DA‐ d 4 ), 4‐hydroxy‐3‐methoxyphenyl‐ d 3 ‐acetic‐ d 2 acid (HVA‐ d 5 ), and γ‐aminobutyric acid‐2,2,3,3,4,4‐ d 6 (GABA‐ d 6 )) were purchased from CDN Isotopes (Quebec, Canada).

Techniques: Comparison, Two Tailed Test

Journal: Journal of Neurochemistry

Article Title: Preserving Neuronal Chemical Messengers: Heat Stabilization Versus Snap Freezing for Improved MALDI Mass Spectrometry Imaging of Brain Tissues

doi: 10.1111/jnc.70122

Figure Lengend Snippet: Imaging experiments comparing the effect of anesthesia on neurotransmitter levels in FF and HS coronal rat brain sections. (a) DA (at bregma 2.28 mm) and (b) 5‐HT (at bregma −2.92 mm) comparing the effect of anesthesia in FF with HS tissues. Color scale bars are shown as a percentage of maximum intensity. Lateral resolution, 150 μm. Data were normalized against the IS DA‐ d 4 . (c) Box plots reflecting normalized average intensity of DA in caudate‐putamen (at bregma 2.28 mm) and 5‐HT in thalamus (at bregma −2.92 mm) comparing the effect of anesthesia in FF and HS brain tissues. All results are expressed as median with interquartile range. Statistical analysis was performed by nonparametric Mann–Whitney U ‐test, without continuity correction. In the CPu, the effect of anesthesia on DA levels was not significant ( p = 0.2, Mann–Whitney U = 1) in both FF and HS groups. Similarly, in the thalamus, the effect of anesthesia on 5‐HT levels was not significant ( p = 0.1, Mann–Whitney U = 0) in both FF and HS groups. FF (fresh frozen)‐anesthetized ( n = 3), non‐anesthetized ( n = 3); HS (heat‐stabilized)‐anesthetized ( n = 3), non‐anesthetized ( n = 3). 5‐HT, serotonin; Anesth., anesthetized; CPu, caudate‐putamen; DA, dopamine; FF, fresh frozen; HS, heat stabilized; Non‐Anesth., non‐anesthetized; Th, thalamus.

Article Snippet: Isotope‐labeled neurotransmitters (dopamine‐1,1,2,2‐ d 4 • HCl (DA‐ d 4 ), 4‐hydroxy‐3‐methoxyphenyl‐ d 3 ‐acetic‐ d 2 acid (HVA‐ d 5 ), and γ‐aminobutyric acid‐2,2,3,3,4,4‐ d 6 (GABA‐ d 6 )) were purchased from CDN Isotopes (Quebec, Canada).

Techniques: Imaging, MANN-WHITNEY