Uthaman M, Srinivasa Reddy Y
Chronobiologia. 1985 Oct-Dec;12(4):331-8.
Changes in the activity of the neurosecretory cells in the cephalothoracic nerve mass (CTNM) of the scorpion, Heterometrus fulvipes (C. Koch) was studied over a 24-h period under natural light-dark cycles. Cytological and cytometric observations revealed that the first 3 groups of type 'A' cells in the sub-oesophageal ganglion of CTNM evidenced ultradian variations in their activity. Two peaks were seen in the activity of these neurosecretory cells, at 12(00) and 00(00). It is inferred that the cells show a biphasic rhythm in the synthesis of two different principles possibly having antagonistic effects on the central nervous system.
