Journal: Cell Reports Medicine

Article Title: Role of dopamine in the development of impaired counterregulation and impaired awareness of hypoglycemia

doi: 10.1016/j.xcrm.2026.102710

Figure Lengend Snippet: Sympathoadrenal response and dopaminergic action with agonist bromocriptine (A–C) Recurrent BROMO administration in i.c.v. reduced food intake and BG response. (A) Schematic diagram of recurrent aCSF ( n = 7) or recurrent BROMO ( n = 7, 2 μg) for 3 days into i.c.v. (B) BG on day 4 following singular injection of INS (15 U/kg NPH) Groups were compared via two-way ANOVA. (C) Cumulative food intake after INS injection (∗ p < 0.005 RBROMO i.c.v. vs. RCSF i.c.v. + INS). Groups were compared via unpaired t test. Each bar represents the mean + SEM. (D–H) Recurrent BROMO administration in i.c.v. and effects on CRR. (D) Schematic diagram of recurrent aCSF ( n = 7) or recurrent BROMO ( n = 7, 2 μg) into i.c.v.. (E) BG during hyperinsulinemic-hypoglycemic clamp where BG is held at 40–45 mg/dL for 90 min. Groups were compared via two-way ANOVA. (F) Ginf. Rate during clamp (∗∗∗∗ p < 0.0001 vs. RBROMO). Groups were compared via unpaired t test. (G) Peak epinephrine concentrations at basal and hypoglycemia (∗ p < 0.005 RCSF vs. RBROMO). Groups were compared via two-way ANOVA. (H) Peak glucagon concentrations at basal and hypoglycemia (∗ p < 0.005 RCSF vs. RBROMO). Groups were compared via two-way ANOVA. Each bar represents the mean + SEM. (I) Dopaminergic gene expression in VTA. Relative gene product expression of COMT, DDC, DRD2, SLC6A3 in the ventral tegmental area following 3-day treatment with RS ( n = 6), RH ( n = 7), or RH + MET ( n = 6) (∗ p < 0.04 RS vs. RH + MET; # p < 0.04 RH vs. RH + MET). Groups were compared via one-way ANOVA. Each bar represents the mean + SEM. (J–O) Recurrent BROMO infusion in VTA effects on CRR. (J) Schematic diagram of recurrent aCSF ( n = 7) or recurrent BROMO (n = 7–9, 5 μg/day; infusion rate 0.1 μL/min). (K) BG concentration during hyperinsulinemic-hypoglycemic clamp, which held BG at 40–50 mg/dL for 90 min. Groups were compared via two-way ANOVA. (L) Ginf. rate during clamp (∗∗∗∗ p < 0.001 RCSF vs. RBROMO). Groups were compared via two-way ANOVA. (M) Peak epinephrine concentrations at basal and hypoglycemia (∗ p < 0.05 BROMO vs. SAL). Groups were analyzed via unpaired t test. (N) Relative gene expression of DRD2 in the ventral tegmental area following a 3-day treatment with either aCSF or BROMO directly into the VTA (∗ p < 0.05 aCSF vs. BROMO). Groups were compared via unpaired t test. (O) Relative gene expression of SLC6A3 in the ventral tegmental area following a 3-day treatment with either aCSF or BROMO directly into the VTA ( p = 0.21). Groups were compared via unpaired t test. Each bar represents the mean + SEM.

Article Snippet: In brief, total RNA was extracted and purified from brain regions using miRNeasy Mini Kit (Qiagen, CA) which was reverse transcribed and then amplified by real-time PCR using Taqman gene assays (Thermo Fisher) for dopamine receptor D2 ( Drd2 ; assay ID: Rn00561126_m1), dopamine transporter or solute carrier family 6, member 3 ( Dat or Slc6a3 ; assay ID: Rn00562224_m1), dopa decarboxylase ( Ddc : assay ID: Rn01401189_m1), catechol- O -methyltransferase ( Comt ; assay ID: Rn00561037_m1) and the housekeeping gene beta-actin ( Actb ; assay ID: Rn00667869_m1).

Techniques: Injection, Gene Expression, Expressing, Concentration Assay

Journal: bioRxiv

Article Title: Enkephalin Gates D2-MSN Disinhibition of the Ventral Pallidum During Cocaine Abstinence

doi: 10.64898/2026.03.11.711212

Figure Lengend Snippet: (A) Cocaine abstinence does not alter mRNA abundance for the dopamine D2 receptor gene ( Drd2 ) in D2-PenkKOs (saline, n = 7; cocaine, n = 7) or littermate Penk f/f controls (saline, n = 10; cocaine, n = 10). (B, D) Example traces of optogenetically-evoked inhibitory post synaptic currents (oIPSC) originating from D2-MSN and recorded in D1-MSNs. Adora2a-Cre controls (B) and D2-PenkKOs (D) were 14 days abstinent from repeated saline or cocaine at the time of recording. (C, E) Quinpirole dose-dependently inhibited oIPSC amplitude in Adora2a-Cre controls (saline: 18 cells/7 mice, cocaine: 13 cells/6 mice) and D2-PenkKOs (saline: 8 cells/3 mice, cocaine: 7 cells/3 mice) (Quinpirole x Cocaine interaction, p < 0.0001). However, quinpirole was less effective at suppressing oIPSCs in cocaine-abstinent mice than the saline-abstinent group. Asterisks represent post-hoc t-tests comparing saline versus cocaine groups and were collapsed across genotype. * p < 0.05: saline vs. cocaine for 0.25 and 0.5 µM. ** p < 0.01: saline vs. cocaine for 1 µM. Data are shown as mean ± SEM, with individual data points labeled as male (circles) and females (triangles).

Article Snippet: Relative mRNA abundance of proenkephalin ( Penk , Mm01212875_m1), dopamine D2 receptor ( Drd2 , Mm00438541_m1), and β-actin ( Actb, Mm01205647_g1) were determined with TaqMan Gene Expression Assay using a CFX384 Real-Time System (initial hold at 95 °C for 20 sec, 40 cycles at 95 °C for 1 sec, and 60 °C for 20 sec).

Techniques: Saline, Labeling

Journal: bioRxiv

Article Title: D2 autoreceptors gate vulnerability to cocaine use disorder

doi: 10.64898/2026.03.10.710882

Figure Lengend Snippet: a , Schematic of the principal contributors to striatal D2/3 ligand binding: postsynaptic D2 heteroreceptors on medium spiny neurons (MSNs; red) and presynaptic D2 autoreceptors on dopamine axons (blue). b , Breeding strategy generating littermates with cell-type–specific Drd2 haploinsufficiency. Genotypes: control (Drd2 loxP/wt ; black), autoD2KD (Drd2 loxP/wt ; Dat IRES-Cre/wt ; blue), MSN-D2KD (Drd2 loxP/wt ; Adora2a-Cre +/– ; red), and double-D2KD (Drd2 flox/wt ; Adora2a-Cre +/– ; Dat IRES-Cre/wt ; purple). Bottom, RT–qPCR quantification of Drd2 mRNA (ΔΔCt) in frontal cortex (open), nucleus accumbens (NAc; dark), and dorsal striatum (light) (n = 5 control; n = 3–5 autoD2KD; n = 5 MSN-D2KD; n = 3–5 double-D2KD). c, e , Representative autoradiographs of [3H]raclopride binding (c) and [3H]SCH23390 binding (e), including nonspecific binding. Color scale indicates nCi/g. Autoradiography was performed in two independent cohorts, each with its own control group; representative control images are therefore shown twice. d, f , Left, schematic of striatal regions of interest used for quantification. Right, specific binding in dorsal striatum and NAc, normalized to the mean of the corresponding control region, for [3H]raclopride (d) and [3H]SCH23390 (f). Symbols denote individual mice; bars show mean ± s.e.m. For binding quantification, n = 3–9 mice per genotype; 8–12 sections per mouse; 24–30 ROIs per animal. *P ≤ 0.05; #0.1 ≥ P > 0.05.

Article Snippet: Relative dopamine D2 receptor (Oa04895884_m1 TaqMan, Catalog #: 4351372 ) and beta-actin probe (Mm01205647_g1 TaqMan, Catalog #: 4331182) mRNA expression were determined with TaqMan Gene Expression Assays (Life Technologies) using a StepOnePlus Real-Time PCR system (Applied Biosystems).

Techniques: Ligand Binding Assay, Control, Quantitative RT-PCR, Binding Assay, Autoradiography