Da. Kendall et al., DIRECT AND INDIRECT STIMULATIONS OF CYCLIC-AMP FORMATION IN HUMAN BRAIN, British Journal of Pharmacology, 105(4), 1992, pp. 899-902
1 Adenosine 3':5'-cyclic monophosphate (cyclic AMP) formation, by use
of an [H-3]-adenine prelabelling assay, was measured in fragments of h
uman cerebral cortex, taken in the course of various neurosurgical pro
cedures. 2 Large accumulations of [H-3]-cyclic AMP due to isoprenaline
, noradrenaline and adenosine and small effects due to forskolin were
observed. Histamine, 5-hydroxytryptamine (5-HT) and the excitatory ami
no acids glutamate and quisqualate were ineffective. 3 The response to
noradrenaline consisted of two components; a direct beta-adrenoceptor
response and an enhancement mediated by an alpha-adrenoceptor which a
ppears to be similar to that in rat cerebral cortex. 4 The response to
isoprenaline was also potentiated by histamine H-1 receptor stimulati
on but the direct effect of 2-chloroadenosine was not altered by hista
mine, 5-HT or quisqualate. 5 It is concluded that some, but not all, o
f the indirect modulations of cyclic AMP formation previously observed
in experimental animal brain exist in human cerebral cortex.