The sensitivity of pineal gland beta-receptors appears to be dependent upon calcium ions.
Rat pineals were used in vitro to demonstrate that calcium antagonists induce a hyposensitive response to stimulation of serotonin N-acetyl transferase (NAT) by the beta-agonist isoproterenol or by dibutyryl cyclic AMP. Mn2+, Co2+ and La3+ at 10(-3)M all significantly reduce the effects of isoproterenol stimulation. In addition, the two enantiomers of D600 also inhibit NAT induction, the D-form slightly more effectively than the L-form. Interestingly, La3+ is also able to inhibit NAT after DBcAMP, indicating that Ca2+ can also control enzyme induction at an intracellular site beyond the beta-receptor.
D000123:Acetyltransferases / Q000378:metabolism; D000818:Animals; D003994:Bucladesine / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D003035:Cobalt / Q000494:pharmacology; D066298:In Vitro Techniques; D007545:Isoproterenol / Q000494:pharmacology; D007811:Lanthanum / Q000494:pharmacology; D008274:Magnesium / Q000494:pharmacology; D010870:Pineal Gland / Q000378:metabolism*; D051381:Rats; D011941:Receptors, Adrenergic / Q000378:metabolism*; D011943:Receptors, Adrenergic, beta / Q000378:metabolism*
D011941:Receptors, Adrenergic; D011943:Receptors, Adrenergic, beta; D003035:Cobalt; D003994:Bucladesine; D007811:Lanthanum; D000123:Acetyltransferases; D008274:Magnesium; D007545:Isoproterenol; D002118:Calcium