Table 1.
Circadian rhythms in dopamine levels.
| Dopamine-Circadian Rhythms | |||||
|---|---|---|---|---|---|
| Reference_ID | Animals | L/D Cycle | Duration | Brain Region | Dopamine Levels |
| Dugovic et al (2009) [54] | Rats | 6h–18h | 6h | Prefrontal Cortex | Higher during DP, lower during DP |
| Barbier et al (2007) [55] | Rats | 6h–18h | 20h | Prefrontal Cortex | Fairly stable |
| Nakayama et al (1993) [56] | Rats | 8h–20h | 24h | Medial Prefrontal Cortex | Higher during DP, lower during LP No effect of extra 12h DP |
| Robinson et al (1991) [57] | Sheep | Natural cycle | 20h | Preoptic Area | Stable during DP, higher during LP |
| Alfinito et al (2009) [58] | Rats | 12:12 | 12h30 | Preoptic Area | Stable |
| Smith et al (1992) [46] | Rats | 7h–19h | 18h | Striatum | Higher during DP, lower during LP |
| Castaneda et al (2004) A1 [59] | Rats | 20h–8h | 30h | Striatum | Lower during DP, higher during LP |
| Castaneda et al (2004) B1 [59] | Rats | 6h DP–24h LP | 30h | Striatum | Higher at DP onset, then decrease and reach its lowest during LP |
| Hood et al (2010) [60] | Rats | 8h–20h | 24h | Striatum | Higher during DP, lower during LP |
| Sano et al (1992) A [47] | Rats, young animals | 6h–18h | 24h | Striatum | Higher during DP, lower during LP |
| Sano et al (1992) B [47] | Rats, old animals | 6h–18h | 24h | Striatum | Same pattern but levels are lower |
| Sano et al (1992) C [47] | Rats, enriched milieu | 6h–18h | 24h | Striatum | Stable |
| Sano et al (1992) D [47] | Rats, isolated | 6h–18h | 24h | Striatum | Stable |
| Decker et al (2005) [53] | Rats | 7h–19h | 48h | Striatum | A few spikes but mean is stable between DP and LP |
| De Marquez-Pardo et al (2000) [52] | Rats | 8h–20h | 24h | Neostriatum | Higher during DP, lower during LP |
| Ferris et al (2014) A [48] | Rats | ZT0–ZT12 | 36h | Caudate Putamen | Higher during DP, lower during LP |
| Ferris et al (2014) B [48] | Mice | ZT0–ZT12 | 38h | Caudate Putamen | Peak at DP onset, higher during DP, lower during LP |
| Ferris et al (2014) C [48] | Mice (DAT KO) | ZT0–ZT12 | 38h | Caudate Putamen | Stable |
| Paulson et al (1994) 1 [61] | Rats | 6h–20h | 20h | Caudate Nucleus | Higher during DP (double the NAC levels), lower during LP |
| Paulson et al (1996) 1 [62] | Rats | 6h–20h | 18h20 | Caudate Nucleus | Higher during DP, lower during LP |
| Murillo-Rodriguez et al (2013) [63] | Rats | 7h–19h | 6h | Nucleus Accumbens | Stable |
| Paulson et al (1994) 2 [61] | Rats | 6h–20h | 20h | Nucleus Accumbens | Stable |
| Paulson et al (1996) 2 [62] | Rats | 6h–20h | 18h20 | Nucleus Accumbens | Higher during DP, lower during LP |
| Castaneda et al (2004) A2 [59] | Rats | 20h–8h | 30h | Nucleus Accumbens | Lower during DP, higher during LP |
| Castaneda et al (2004) B2 [59] | Rats | 6h DP–24h LP | 30h | Nucleus Accumbens | Higher during DP, lower during LP |
| Verhagen et al (2009) [64] | Rats | 2h–14h | 36h | Lateral to Nucleus Accumbens Shell | Higher during DP, lower during LP |
| Fetissov et al (2000) 1 [65] | Rats | 6h–18h | 24h | Lateral Hypothalamus | Peak at DP onset, then start to decrease after 2h. Stay stable during LP |
| Fetissov et al (2000) 2 [65] | Rats | 6h–18h | 24h | Ventromedial Hypothalamus | Gradually decrease |
| Izumo et al (2012) [66] | Rats | 7h–19h | 15h | Central Nucleus of the Amygdala | Higher during DP, lower during LP (wide error bars) |
Each row represents one study (i.e. an experimental group within a publication) and a qualitative description of the results. Fluctuations are described as “higher” and “lower” disregarding actual magnitude of changes. Rows are sorted by brain region. Lower case letters indicate separate publications from the same authors in the same year; upper cases letters represent separate groups within publications; numbers represent separate brain regions within animals.
Abbreviations: L/D cycle: Light-Dark Cycle; LP: Light Phase; DP: Dark Phase; DAT KO: Dopamine Transporter Knock Out; ZT: Zeitgeber.