In vivo and in vitro comparison of the clock gene expressions in the pineal gland under acute and synchronized noradrenergic stimulation.

• Grant number: 09/10435-9
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: October 01, 2009
• End date: September 30, 2010
• Field of knowledge: Biological Sciences - Physiology - General Physiology
• Principal Investigator: José Cipolla Neto
• Grantee: Jéssica Andrade da Silva
• Host Institution: Instituto de Ciências Biomédicas (ICB). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated research grant: 04/06767-2 - Melatonin and the control of energy metabolism: central and peripheral actions and their interaction with other hormones, AP.TEM

Abstract

Melatonin, the pineal gland hormone which is synthesized at night, shows a circadian and seasonal rhythm. Its synthesis is synchronized to the light/dark cycle and to the photoperiod duration through the year, transmitted to the gland through the retino-hypothalamic pathway. Melatonin synthesis is induced by norepineprhine release in the gland perivascular space at night, also modulated by peptidergic systems. The central and peripheral clock genes expression including the pineal gland is responsable to regulate the activity and expression of other genes and proteins (i.g. clock controlled genes - ccg), driving the daily metabolic expression of suitable tissue. As the circadian pineal gland function is strictly determined by norepinephrine nocturnal release, we intend to compare the daily rhythmic expression of bmal1, clock, rev-erba, per 1, 2 e 3, cry 1,2 e dbp (ccg), in 4 conditions (1 in vivo and 3 in vitro): 1-) light dark cycle synchronized animals (12h:12h), sacrificed every 3 hours over 24 hours; 2-) pineal glands kept in culture without any treatment; 3-) pineal glands kept in culture stimulated by norepinephrine for 12 hours; 4-) pineal glands kept in culture stimulated by norepinephrine every 12 hours (12 hours stimulated, 12 hours absence stimulation) since beginning of the culture. For all culture groups the cultivating time will be 72 hours and all treatment will be performed after 48 hours of culture, except for the 4th condition and all glands will be collected every 3 hours in the last 24 hours of the culture.