Melatonin synthesis in the optic lobes and midbrain of the grasshopper
            Oedipoda caerulescens

Raúl Vieira; María J. Mancebo; Jorge José Pérez‐Maceira; Manuel Aldegunde

doi:10.1002/arch.21605

Melatonin synthesis in the optic lobes and midbrain of the grasshopper Oedipoda caerulescens

Archives of Insect Biochemistry and Physiology ◽

10.1002/arch.21605 ◽

2019 ◽

Vol 102 (4) ◽

Author(s):

Raúl Vieira ◽

María J. Mancebo ◽

Jorge José Pérez‐Maceira ◽

Manuel Aldegunde

Keyword(s):

Optic Lobes ◽

Melatonin Synthesis ◽

Oedipoda Caerulescens

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Monosodium glutamate administration early in life alters pineal melatonin nocturnal profile in adulthood

Melatonin Research ◽

10.32794/mr11250084 ◽

2021 ◽

Vol 4 (1) ◽

pp. 99-114

Author(s):

Janaína B Garcia ◽

Fernanda G Do Amaral ◽

Daniela C Buonfiglio ◽

Rafaela FA Vendrame ◽

Patrícia L Alves ◽

...

Keyword(s):

Insulin Resistance ◽

Body Weight ◽

Pineal Gland ◽

Serum Insulin ◽

Monosodium Glutamate ◽

Female Rats ◽

Pineal Melatonin ◽

Melatonin Synthesis ◽

Male And Female Rats ◽

Melatonin Production

The pineal gland synthesizes melatonin exclusively at night, which gives melatonin the characteristic of a temporal synchronizer of the physiological systems. Melatonin is a regulator of insulin activities centrally and also peripherally and its synthesis is reduced in diabetes. Since monosodium glutamate (MSG) is often used to induce the type 2 diabetic and metabolic syndrome in animal models, the purpose of this work is to evaluate the potential effects of MSG given to neonates on the pineal melatonin synthesis in different aged male and female rats. Wistar rats were subcutaneously injected with MSG (4mg/g/day) or saline solution (0.9%) from the second to eighth post-natal day. The circadian profiles both melatonin levels and AANAT activity were monitored at different ages. Body weight, naso-anal length, adipose tissues weight, GTT, ITT and serum insulin levels were also evaluated. Typical obesity with the neonatal MSG treatment was observed, indicated by a great increase in adipose depots without a concurrent increase in body weight. MSG treatment did not cause hyperglycemia or glucose intolerance, but induced insulin resistance. An increase of melatonin synthesis at ZT 15 with phase advance was observed in in some animals. The AANAT activity was positively parallel to the melatonin circadian profile. It seems that MSG causes hypothalamic obesity which may increase AANAT activity and melatonin production in pineal gland. These effects were not temporally correlated with insulin resistance and hyperinsulinemia indicating the hypothalamic lesions, particularly in arcuate nucleus induced by MSG in early age, as the principal cause of the increase in melatonin production.

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