Abstract
In male rats housed under a 14:10 LD cycle (lights on at 0600h), pineal beta-adrenergic receptors, assessed as 125Iodopindolol (IPIN) binding to membrane preparations, showed a 24 hour variation characterized by a nocturnal increase that peaked around middark (2300h-0200h) and a decrease during the latter half of the dark period. Animals exposed to light for 3 hours into the normal dark period showed a similar increase in IPIN binding that was prevented by a single sc injection (0.5 mg/kg) of isoproterenol (ISO). The decrease in IPIN binding observed after middark was prevented both by moving the animals to light at 0200h and by propranolol administration (20 mg/kg). Likewise, the reduction in IPIN binding was induced in light exposed animals both by ISO administration (in a dose dependent manner) and by injection of norepinephrine (NE) plus the catecholamine uptake blocker desmethylimipramine (DMI). DMI alone was without effect. Chronic denervation of the pineal gland by superior cervical ganglionectomy (SCGx) increased IPIN binding to levels not higher than those observed at middark. The results suggest that rat pineal beta-adrenergic receptors are regulated in a rhythmic 24 hour pattern. A decrease in density (downregulation) induced by a darkness-associated increase in NE release, occurs late in the night before lights on; recovery from the down regulated state (upregulation) occurs during the light and early dark phase, reaching a maximum density of beta-adrenergic receptors at middark not different from that observed in chronically denervated pineal glands.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 707-714 |
| Number of pages | 8 |
| Journal | Life Sciences |
| Volume | 43 |
| Issue number | 8 |
| DOIs | |
| State | Published - 1988 |
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ASJC Scopus subject areas
- Pharmacology
Cite this
Darkness-induced changes in noradrenergic input determine the 24 hour variation in beta-adrenergic receptor density in the rat pineal gland : In vivo physiological and pharmacological evidence. / Gonzalez-Brito, Aldo; Reiter, Russel J; Menendez-Pelaez, Armando; Guerrero, Juan M.; Santana, Celsa; Jones, David J.
In: Life Sciences, Vol. 43, No. 8, 1988, p. 707-714.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Darkness-induced changes in noradrenergic input determine the 24 hour variation in beta-adrenergic receptor density in the rat pineal gland
T2 - In vivo physiological and pharmacological evidence
AU - Gonzalez-Brito, Aldo
AU - Reiter, Russel J
AU - Menendez-Pelaez, Armando
AU - Guerrero, Juan M.
AU - Santana, Celsa
AU - Jones, David J.
PY - 1988
Y1 - 1988
N2 - In male rats housed under a 14:10 LD cycle (lights on at 0600h), pineal beta-adrenergic receptors, assessed as 125Iodopindolol (IPIN) binding to membrane preparations, showed a 24 hour variation characterized by a nocturnal increase that peaked around middark (2300h-0200h) and a decrease during the latter half of the dark period. Animals exposed to light for 3 hours into the normal dark period showed a similar increase in IPIN binding that was prevented by a single sc injection (0.5 mg/kg) of isoproterenol (ISO). The decrease in IPIN binding observed after middark was prevented both by moving the animals to light at 0200h and by propranolol administration (20 mg/kg). Likewise, the reduction in IPIN binding was induced in light exposed animals both by ISO administration (in a dose dependent manner) and by injection of norepinephrine (NE) plus the catecholamine uptake blocker desmethylimipramine (DMI). DMI alone was without effect. Chronic denervation of the pineal gland by superior cervical ganglionectomy (SCGx) increased IPIN binding to levels not higher than those observed at middark. The results suggest that rat pineal beta-adrenergic receptors are regulated in a rhythmic 24 hour pattern. A decrease in density (downregulation) induced by a darkness-associated increase in NE release, occurs late in the night before lights on; recovery from the down regulated state (upregulation) occurs during the light and early dark phase, reaching a maximum density of beta-adrenergic receptors at middark not different from that observed in chronically denervated pineal glands.
AB - In male rats housed under a 14:10 LD cycle (lights on at 0600h), pineal beta-adrenergic receptors, assessed as 125Iodopindolol (IPIN) binding to membrane preparations, showed a 24 hour variation characterized by a nocturnal increase that peaked around middark (2300h-0200h) and a decrease during the latter half of the dark period. Animals exposed to light for 3 hours into the normal dark period showed a similar increase in IPIN binding that was prevented by a single sc injection (0.5 mg/kg) of isoproterenol (ISO). The decrease in IPIN binding observed after middark was prevented both by moving the animals to light at 0200h and by propranolol administration (20 mg/kg). Likewise, the reduction in IPIN binding was induced in light exposed animals both by ISO administration (in a dose dependent manner) and by injection of norepinephrine (NE) plus the catecholamine uptake blocker desmethylimipramine (DMI). DMI alone was without effect. Chronic denervation of the pineal gland by superior cervical ganglionectomy (SCGx) increased IPIN binding to levels not higher than those observed at middark. The results suggest that rat pineal beta-adrenergic receptors are regulated in a rhythmic 24 hour pattern. A decrease in density (downregulation) induced by a darkness-associated increase in NE release, occurs late in the night before lights on; recovery from the down regulated state (upregulation) occurs during the light and early dark phase, reaching a maximum density of beta-adrenergic receptors at middark not different from that observed in chronically denervated pineal glands.
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U2 - 10.1016/0024-3205(88)90142-7
DO - 10.1016/0024-3205(88)90142-7
M3 - Article
C2 - 2842566
AN - SCOPUS:0023794784
VL - 43
SP - 707
EP - 714
JO - Life Sciences
JF - Life Sciences
SN - 0024-3205
IS - 8
ER -