Transcript Slide 1

Adenosine and Dopamine Receptor Interactions in the
Striatum and Caffeine-Induced Behavioral Activation
Vickram Ramkumar, Ph.D. and Linda Toth, DVM, Ph.D.
Department of Pharmacology
Southern Illinois University School of Medicine
Springfield, IL
Adenosine Receptor – Reactive Oxygen
Species Interaction (ROS)
Nuclear Factor kB
AR
ROS
Antioxidant Enzymes
Are Adenosine Receptors Markers of
Oxidative Stress?
Previous Observations
 Chemotherapeutic drugs which increase ROS generation increase
adenosine A1 receptor by activating nuclear factor kB (Nie et al., 1998)
 Nerve growth factor induces the expression of the adenosine A2A receptor
by activating nuclear factor kB (Nie et al., 1999)
 NF-κB induces the expression of the A2AAR while A2AAR suppresses
NF-kB activation (Sands et al., 2004; Murphee et al., 2008)
 Deletion of the p50 subunit of NF-kB decreased A1AR and D2R expression
and increased A2AAR expression (Jhaveri et al., 2007; Xie et al., 2008)
 NF-κB dependent induction of dopamine D2 receptor (Fiorentini et al., 2002)
Conclusion: NF-kB plays an integral role in the regulation of adenosine and
dopamine signaling
Cisplatin Oxidative Stress Induces Cochlear A1AR
Ford et al., 1997 Hear Res. 111, 143-152
OXIDATIVE STRESS INDUCES AI ADENOSINE RECEPTORS
Nie et al., 1998
Mol. Pharmacol. 53, 663-669
Cisplatin Induces NF-kB Activation
Nie et al., Mol. Pharmacol. 53, 663-669
Nerve Growth Factor suppresses
A2AAR expression through
activation of NF-κB
Nie et al., 1999; Mol. Pharmacol. 56, 947-954
What is NF-kappa B?
ROS
(Modified from)
(A1AR,. A2AAR)
Does Disruption of NF-kB Function Alter
Expression of A1 and A2AAR?
(B6129PF2/J)
(B6129P-Nfkb1 (tmbl)
Hypothesis: Disruption of NF-κB would lead to lower A1AR and
higher A2AAR expression.
Decreased Expression of A1AR in the Mouse Striatum
Xie et al., 2007 Life Sci. 1031-1041
Increased Striatal Expression of A2AAR in p50-/- Mouse
Xie et al., 2007 Life Sci. 1031-1041
Decreased Striatal Expression
of D2 Dopamine Receptor in
p50-/- Mouse
Xie et al., 2007 Life Sci. 1031-1041
Regulation of G Proteins in the p50-/- Mouse Striatum
Xie et al., 2007 Life Sci. 1031-1041
SUMMARY
 Decreased expression of the A1AR
 Increased expression of the A2AAR
 Decreased expression of D2R
 Increased Golf/s proteins & decreased Gi
Striatal Adenosine/Dopamine Receptors Distribution
A2AAR
D2R
A1AR
Golf/s
Purported AR/DR Signaling
Cascade in Striatum
D1R
Gi
Cyclic AMP
Protein Kinase A
CREB
IEGs
GABAergic Neuron
Activity
Do Alterations in Striatal Adenosine and Dopamine Receptors
in p50-/- Mouse Striatum Confer Behavioral Differences?
(300 mg/L)
(20 g/L)
(Intraperitoneal transmitter and DSI receiver under each cage)
F2: 101 mg/kg/24 h;
p50-/- 107 mg/kg/24 h
Increased Sensitivity of p50-/- Mice to the Locomotor Stimulatory Action
of A2AAR Antagonist
Locomotor activity
(counts per 10 mi)
35
*
30
F2 Basal
KO Basal
25
F2 SCH 58261 (10 mg/kg, i.p.)
KO SCH 58261
20
15
10
5
0
0
10
20
30
40
50
60
70
80
90
100 110 120
Locomotor activity
(counts per 10 mi)
Minutes after administration of SCH 58261
30
F2 Basal
KO Basal
25
20
F2 DPCPX (5 mg/kg, i.p.)
KO DPCPX
15
10
5
0
0
10
20
30
40
50
60
70
80
90
100 110 120
Minutes after administration of DPCPX
D2R Antagonist Reversed the Stimulatory Action of A2AAR Antagonist
F2 Basal
Locomotor activity
(counts per 10 min)
30
Raclopride (0.5 mg/kg, i.p.)
SCH 58621 (10 mg/kg, i.p)
DPCPX (5 mg/kg, i.p)
25
KO Basal
F2 rac+SCH
20
KO rac+SCH
15
10
5
0
0
10
20
30
40
50
60
70
80
90
100
110
120
Minutes after administration of SCH 58621
Locomotor activity
(counts per 10 min)
30
F2 Basal
25
KO Basal
F2 SCH+DPCPX
20
KO SCH+DPCPX
15
10
5
0
0
10
20
30
40
50
60
70
80
90
100 110 120
Minutes after administration of SCH 58621 and DPCPX
No Change in Caffeine Levels in Serum and Brain between F2 and p50-/- Mice
A.
Serum Caffeine (ug/ml)
B.
F2, n = 3-6
KO, n = 6
16
14
12
10
8
6
4
2
0
F2 (n = 4)
KO (n = 3)
1
4
Hours after oral administration
16
14
12
10
8
6
4
2
0
D.
●┼
Caffeine in Brain (ug/g)
Caffeine in brain (ug/g)
C.
KO
F2
0
5
10
15
20
Minutes after injection
25
30
10
8
6
4
2
0
1
4
Hours after oral administration
Summary
 p50-/- mice do not show any differences in basal locomotor activity.
 p50-/- mice are more sensitive to the locomotor stimulatory effect of
caffeine and A2AAR antagonist but not A1AR antagonist.
 p50-/- mice show reduced dopamine turnover but no change in dopamine
transporter or altered caffeine pharmacokinetics.
AR/DR Signaling in p50-/- Mouse Striatum
Adenosine/Dopamine Neurotransmission in the Striatum
Adenosine/Dopamine Neurotransmission in the Striatum
Changes in p50-/- Striatum
Receptors
G protein/
second messengers
Kinases
Behavior
Acknowledgements
Linda Toth, DVM, Ph.D.
Xiaobin Xie, Ph.D.
Krishna Jhaveri, Ph.D.
Lydia Abrogast, Ph.D.
Zhongzhen Nie, M.D., Ph.D – Univ. Georgia, Augusta, GA
Gary Stiles, M.D. – Duke University, Durham, NC
Honzhou Ren, Ph.D. – Duke University, Durham, NC
NIH Grants NIHLB, NIDCD, SIU CRC Funds