Regulation of glycogen content in rat pineal gland by norepinephrine

Eliseo A. Eugenín; Claudia G. Sáez; Gladys Garcés; Juan C. Sáez

doi:10.1016/S0006-8993(97)00273-4

Regulation of glycogen content in rat pineal gland by norepinephrine

Eliseo A. Eugenín, Claudia G. Sáez, Gladys Garcés, Juan C. Sáez

Research output: Contribution to journal › Article › peer-review

6 Scopus citations

Abstract

In the rat pineal gland the glycogen stores were cytochemically localized in astrocytes and pinealocytes. Moreover, it was found that norepinephrine (NE) induced a time- and concentration-dependent reduction in pineal glycogen content and yielded lactic acid. The NE effect was prevented by blocking α₁- but not α₂ or β-adrenoceptors. Activation of α₂- adrenoceptors induced a small decrease in glycogen levels that could have pre- and postsynaptic components. Activation of β-adrenoceptors with 10^- ¹²-10^-3 M isoproterenol (ISO) induced a bell shape concentration- response curve, presumably due to desensitization, since the response induced by 10^-4 M ISO was greater with shorter period of stimulation. On the other hand, activation of α₁-adrenoceptors with 10^-12-10^-3 M phenylephrine (PHN) induced a hyperbolic concentration-response curve with a maximum at concentrations above 10^-8 M. Moreover, treatment with ISO drastically reduced the response induced by PHN concentrations lower but not higher than 10^-6 M, favoring a concentration-dependent response between 10^-6 and 10^- ⁴ M PHN, similar to that induced by equimolar NE concentrations. Thus, the NE-induced reduction in glycogen content of the rat pineal gland is mainly mediated by α-adrenoceptors and modulated by intracellular mechanisms by β- adrenoceptors.

Original language	English (US)
Pages (from-to)	34-41
Number of pages	8
Journal	Brain Research
Volume	760
Issue number	1-2
DOIs	https://doi.org/10.1016/S0006-8993(97)00273-4
State	Published - Jun 20 1997
Externally published	Yes

Keywords

Adrenoceptor
Desensitization
Epiphysis cerebri
Glycogen
Lactic acid
Norepinephrine

ASJC Scopus subject areas

General Neuroscience
Molecular Biology
Clinical Neurology
Developmental Biology

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10.1016/S0006-8993(97)00273-4

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@article{74e1b1259f3c44f48396fdf9190ebad0,

title = "Regulation of glycogen content in rat pineal gland by norepinephrine",

abstract = "In the rat pineal gland the glycogen stores were cytochemically localized in astrocytes and pinealocytes. Moreover, it was found that norepinephrine (NE) induced a time- and concentration-dependent reduction in pineal glycogen content and yielded lactic acid. The NE effect was prevented by blocking α1- but not α2 or β-adrenoceptors. Activation of α2- adrenoceptors induced a small decrease in glycogen levels that could have pre- and postsynaptic components. Activation of β-adrenoceptors with 10- 12-10-3 M isoproterenol (ISO) induced a bell shape concentration- response curve, presumably due to desensitization, since the response induced by 10-4 M ISO was greater with shorter period of stimulation. On the other hand, activation of α1-adrenoceptors with 10-12-10-3 M phenylephrine (PHN) induced a hyperbolic concentration-response curve with a maximum at concentrations above 10-8 M. Moreover, treatment with ISO drastically reduced the response induced by PHN concentrations lower but not higher than 10-6 M, favoring a concentration-dependent response between 10-6 and 10- 4 M PHN, similar to that induced by equimolar NE concentrations. Thus, the NE-induced reduction in glycogen content of the rat pineal gland is mainly mediated by α-adrenoceptors and modulated by intracellular mechanisms by β- adrenoceptors.",

keywords = "Adrenoceptor, Desensitization, Epiphysis cerebri, Glycogen, Lactic acid, Norepinephrine",

author = "Eugen{\'i}n, {Eliseo A.} and S{\'a}ez, {Claudia G.} and Gladys Garc{\'e}s and S{\'a}ez, {Juan C.}",

note = "Funding Information: This work was supported in part by grants of FONDECYT to J.C.S. (1930690 and 1960559) and to C.G.S. (Post-doc 3930011).",

year = "1997",

month = jun,

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doi = "10.1016/S0006-8993(97)00273-4",

language = "English (US)",

volume = "760",

pages = "34--41",

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TY - JOUR

T1 - Regulation of glycogen content in rat pineal gland by norepinephrine

AU - Eugenín, Eliseo A.

AU - Sáez, Claudia G.

AU - Garcés, Gladys

AU - Sáez, Juan C.

N1 - Funding Information: This work was supported in part by grants of FONDECYT to J.C.S. (1930690 and 1960559) and to C.G.S. (Post-doc 3930011).

PY - 1997/6/20

Y1 - 1997/6/20

N2 - In the rat pineal gland the glycogen stores were cytochemically localized in astrocytes and pinealocytes. Moreover, it was found that norepinephrine (NE) induced a time- and concentration-dependent reduction in pineal glycogen content and yielded lactic acid. The NE effect was prevented by blocking α1- but not α2 or β-adrenoceptors. Activation of α2- adrenoceptors induced a small decrease in glycogen levels that could have pre- and postsynaptic components. Activation of β-adrenoceptors with 10- 12-10-3 M isoproterenol (ISO) induced a bell shape concentration- response curve, presumably due to desensitization, since the response induced by 10-4 M ISO was greater with shorter period of stimulation. On the other hand, activation of α1-adrenoceptors with 10-12-10-3 M phenylephrine (PHN) induced a hyperbolic concentration-response curve with a maximum at concentrations above 10-8 M. Moreover, treatment with ISO drastically reduced the response induced by PHN concentrations lower but not higher than 10-6 M, favoring a concentration-dependent response between 10-6 and 10- 4 M PHN, similar to that induced by equimolar NE concentrations. Thus, the NE-induced reduction in glycogen content of the rat pineal gland is mainly mediated by α-adrenoceptors and modulated by intracellular mechanisms by β- adrenoceptors.

AB - In the rat pineal gland the glycogen stores were cytochemically localized in astrocytes and pinealocytes. Moreover, it was found that norepinephrine (NE) induced a time- and concentration-dependent reduction in pineal glycogen content and yielded lactic acid. The NE effect was prevented by blocking α1- but not α2 or β-adrenoceptors. Activation of α2- adrenoceptors induced a small decrease in glycogen levels that could have pre- and postsynaptic components. Activation of β-adrenoceptors with 10- 12-10-3 M isoproterenol (ISO) induced a bell shape concentration- response curve, presumably due to desensitization, since the response induced by 10-4 M ISO was greater with shorter period of stimulation. On the other hand, activation of α1-adrenoceptors with 10-12-10-3 M phenylephrine (PHN) induced a hyperbolic concentration-response curve with a maximum at concentrations above 10-8 M. Moreover, treatment with ISO drastically reduced the response induced by PHN concentrations lower but not higher than 10-6 M, favoring a concentration-dependent response between 10-6 and 10- 4 M PHN, similar to that induced by equimolar NE concentrations. Thus, the NE-induced reduction in glycogen content of the rat pineal gland is mainly mediated by α-adrenoceptors and modulated by intracellular mechanisms by β- adrenoceptors.

KW - Adrenoceptor

KW - Desensitization

KW - Epiphysis cerebri

KW - Glycogen

KW - Lactic acid

KW - Norepinephrine

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ER -

Regulation of glycogen content in rat pineal gland by norepinephrine

Abstract

Keywords

ASJC Scopus subject areas

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