Effects of synthetic cannabinoids, identified in smoked herbal products, on synaptic transmission in the brain
Bela Szabo, Mario Lederer, Eszter Boros Inst. f. Pharmakologie Albert-Ludwigs-Universität Freiburg 1) Cannabinoid receptors and their typical effects in the brain Cannabinoid receptors
NATURAL NH2 NH CB1 2 CB2
COOH COOH OH 9-tetrahydrocannabinol
O
Gi/o proteins ENDOGENOUS
O OH N H neurons immune cells anandamide
O OH O OH
2-arachidonoylglycerol CB1-Rezeptoren im menschlichen Gehirn: PET-Untersuchung mit [18F]MK-9470
Negative correlation: extravagance – CB1 receptor Van Laere et al., Arch Gen disorderlinessVan Laere – CB et1 al.,receptor NeuroimagePsychiatry 39: 1533-1541, 66:196-204, 20082009 2) Synthetic cannabinoids Synthetic cannabinoids from Sterling Winthrop
O indomethacin pravadoline O O O N O N Cl O N
O
WIN55212
N O O N
Ward et al., J Pharmacol Exp Ther 255: 1230-1239, 1990 O Haubrich et al., J Pharmacol Exp Ther 255: 511-522, 1990 Kuster et al., J Pharmacol Exp Ther 264: 1352-1363, 1993 Synthetic cannabinoids from John William Huffman: JWH-compounds
JWH-018 JWH-210
O N O N
O
JWH-122 JWH-081 Aung et al., Drug Alcohol Depend 60: 133-140, 2000 Huffman JW, Cannabimimetic indoles, pyrroles, and O N O N indenes: structure–activity relationships and receptor Interactions. In: Reggio PH (ed), The Cannabinoid Receptors, The Receptors, Humana Press, 2009, pp 49- 94 3) Methods Patch-Clamp-Setup
Verstärker
Rollquetschpumpe Objektiv Patch-Pipette Teflonschlauch
Badkammer Absaugung Hirnschnitt Begasung mit Carbogen
(95% O2; 5% CO2)
Becherglas mit ACSF Cerebellum: microscopic views
white matter granule cell layer Purkinje cell layer molecular layer
basket cell molecular layer Purkinje cell CB -R Purkinje cell 1 layer patch pipette sIPSC recording granule cell depolarisation layer
4) Synthetic cannabinoids inhibit synaptic transmission WIN55212-2 inhibits GABAergic synaptic transmission JWH-018 inhibits GABAergic synaptic transmission JWH-210 inhibits GABAergic synaptic transmission 5) Synthetic cannabinoids interfere with endocannabinoid-mediated retrograde signal transmission Retrograde signaling by cannabinoids
Purkinje cell soma / dendrite
mG lu 1 R 1 basket cell / q axon terminal G
Ca2+ GABA-R GABA
Vm endocannabinoid (2-AG) 1-R CB
THC, WIN, JWH-018, JWH-210 depolarisation Depolarisation-induced suppression of inhibition (DSI)
120 depol (9P) 120 1 100 100
80 80
60 60 PRE 2 PRE sIPSC amplitude [% of PRE] sIPSC [% frequency of PRE] 050100150s 0 50 100 150 s
PRE (1) 120
100
80 0.5 nA
[% of PRE] DSI (2) 2 s 60 PRE
sIPSC cumulative amplitude sIPSC cumulative 0 50 100 150 s JWH-210 occludes DSI
depol 120 depol depol 100 SOL superfusion 80 * 60 PRE
sIPSC frequency [% of PRE] 0 50 100 150 s
depol 120 * depol depol 100 * JWH-210 5 x 10-6 M superfusion 80
60 PRE
sIPSC [% frequency of PRE] 0 50 100 150 s Effects of synthetic cannabinoids, identified in smoked herbal products, on synaptic transmission in the brain
) The synthetic aminoalkylindole cannabinoids WIN5512-2, JHW-018 and JWH-210 inhibit GABAergic synaptic transmission in the cerebellar cortex
2) The basis of the inhibition is very likely inhibition of GABA release from the presynaptic axon terminals
3) The synthetic cannabinoids occlude endocannabinoid-mediated retrograde signal transmission between neurons, indicating that they can interfere with elementary neuronal learning basket processes cell
Purkinje CB -R cell 1
WIN, JWH endocannabinoid depolarisation End