Functional heterogenity of pinealocytes in connection with different mediators influence

Sibarov D.A., Kovalenko R.I., Nozdrachev A.D
Functional heterogenity of pinealocytes in connection with different mediators influence.
27th Gottingen Neurobiology Conference, Gottingen, Germany (May 27-30) 1999.

General physiology department of St.Petersburg State University, 199034, University emb. 7/9, St.Petersburg, Russia.

An extracellular electrophysiological study of the pineal gland of 15 male Wistar rats (180-200g) in osmotic stress conditions (after 48-hours water and food deprivation) was performed in the day time. Osmotic stress increases pineal activity, even in hte day-time (Kovalenko, Sibarov, 1997, Adv.in.Compar.Endocr., "13th Int. Congr. Of Comparat. Endocr.", Yokogama, Japan, 1997). Two main significantly different types of spikes were investigated - "fast" (> 4 spikes/sec) a nd "slow" (<2spikes/sec). "Slow"-type cells were presented by regular, irregular and pattern types of cellular activity. The frequency of spikes on pinealocytes reflects the intensity of exocytosis. Spontaneously active pineal cells were tested with m icroinjections of norepinephrine (NE) and alpha- and beta-adrenoblocators (phentolamine and anapriline) through the tip of the microelectrode (5-7MOhm), and with electric stimulation of olfactory epithelium. Olphactory stimulation suppressed activity of only "slow" type cells. No significant changes of pinealocytes activity was noticed after NE applications. Both alpha- and beta-adrenoblockators caused short (2-3 minutes) increase of spikes frequency of "fast"-type cells. NE can increase or suppress an activity of different populations of pinealocytes (Semm, 1981, Exp.Brain.Res,43). We have supposed that an absence of effect up on the pinealocytes discharging while NE injections is connected with it's high background concentration in the pineal parenchyma in stress. In this conditions an adrenoblockator probably takes away an adrenergic influence on pinealocytes and consequentl y changes frequency of some cells. According to data of adrenoblockators influence on "fast"-type cells, we think this cells to be controlled by adrenergic input, whereas "slow"-type cells are modulated by non-adrenergic olfactory sensory input (see figure).

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Sibarov D.A., Kovalenko R.I., Nozdrachev A.D Functional heterogenity of pinealocytes in connection with different mediators influence. 27th Gottingen Neurobiology Conference, Gottingen, Germany (May 27-30) 1999. General physiology department of St.Petersburg State University, 199034, University emb. 7/9, St.Petersburg, Russia. An extracellular electrophysiological study of the pineal gland of 15 male Wistar rats (180-200g) in osmotic stress conditions (after 48-hours water and food deprivation) was performed in the day time. Osmotic stress increases pineal activity, even in hte day-time (Kovalenko, Sibarov, 1997, Adv.in.Compar.Endocr., "13th Int. Congr. Of Comparat. Endocr.", Yokogama, Japan, 1997). Two main significantly different types of spikes were investigated - "fast" (> 4 spikes/sec) a nd "slow" (<2spikes/sec). "Slow"-type cells were presented by regular, irregular and pattern types of cellular activity. The frequency of spikes on pinealocytes reflects the intensity of exocytosis. Spontaneously active pineal cells were tested with m icroinjections of norepinephrine (NE) and alpha- and beta-adrenoblocators (phentolamine and anapriline) through the tip of the microelectrode (5-7MOhm), and with electric stimulation of olfactory epithelium. Olphactory stimulation suppressed activity of only "slow" type cells. No significant changes of pinealocytes activity was noticed after NE applications. Both alpha- and beta-adrenoblockators caused short (2-3 minutes) increase of spikes frequency of "fast"-type cells. NE can increase or suppress an activity of different populations of pinealocytes (Semm, 1981, Exp.Brain.Res,43). We have supposed that an absence of effect up on the pinealocytes discharging while NE injections is connected with it's high background concentration in the pineal parenchyma in stress. In this conditions an adrenoblockator probably takes away an adrenergic influence on pinealocytes and consequentl y changes frequency of some cells. According to data of adrenoblockators influence on "fast"-type cells, we think this cells to be controlled by adrenergic input, whereas "slow"-type cells are modulated by non-adrenergic olfactory sensory input (see figure).