Fig. 1
Immunoblotting of rat hypothalamus (HT) with MT1 and MT2 receptors antibodies. A) Immunoblot of rat hypothalamic tissue with anti-MT1 antibody. B) Same as in A but with anti-MT2 antibody.
Fig. 2
MT1 receptors localization in the cortex and the hippocampus. A) low and C) high magnification pictures showing label of hippocampal neurons with anti-MT1 antibody. Scale bars are 80 and 20 µm respectively. B) and D) show labeling with anti-MT1 antibody in cortical neurons in low and high magnification respectively. Scale bars are 80 and 20 µm respectively.
Fig. 3
MT1 receptors localization in rat SCN across the circadian cycle. Labeling with MT1 antibody in the SCN is shown at A) midday ZT 5–7, B) dusk ZT 11–13, C) midnight ZT 23–01, and D) dawn ZT 17–19, respectively. 3V indicates the third ventricle, OC is the optic chiasm. Scale bar in each picture is 80 µm.
Fig. 4
Circadian rhythm of MT1 receptors density in the SCN. Normalized pixel density is plotted at different CTs. * and ** indicates that p value is less than 0.5 and less than 0.01 respectively, ns statistically insignificant.
Fig. 5
MAP2 staining in the SCN and optic chiasm. A) Labeling of the dendrites within the SCN is shown with red color. The arrow points to a neuron within the optic chiasm. B) An overlay of both DAPI labeling the nuclei (blue) and MAP2 labeling the dendrites (Red). C) Same as in B but in a different section; notice a more distant neuron within the SCN (arrows). 3V indicates the third ventricle. OC is the optic chiasm. Scale bar is 20 µm.
Fig. 6
MT2 receptors immunostaining in the SCN. 3V indicates the third ventricle, OC is the optic chiasm. Scale bar is 80 µm.
Fig. 7
MT2 receptor immunolabeling in the paraventricular nucleus. 3V is the third ventricle. Scale bar is 80 µm.
Fig. 8
The possible feedback of melatonin on the SCN. RHT is the retinohypothalamic tract, GHT is the geniculohypothalamic tract, PVN is the paraventricular nucleus, and SCG is the superior cervical ganglia. Plus sign (+) indicates stimulation while negative sign (-) indicates inhibition.