Monoamine metabolism and sympathetic nervous activation following subarachnoid haemorrhage: influence of gender and hydrocephalus.
Subarachnoid haemorrhage is a serious condition, often accompanied by cerebral vasospasm and hydrocephalus, which may result in delayed cerebral ischaemia and neurological deterioration. While the mechanisms responsible remain unknown, activation of the sympathetic nervous system, leading to elevated levels of circulating catecholamines is, at least in part, implicated. In this study, we sought to examine the importance of sympathetic nervous activation and its relation to brain monoaminergic neurotransmission in 25 patients following subarachnoid haemorrhage by examining plasma and cerebrospinal fluid levels of the catecholamines noradrenaline, adrenaline and dopamine, and their metabolites. Total body sympathetic activity was concurrently assessed using isotope dilution methodology. In the early phase following subarachnoid haemorrhage patients exhibited markedly elevated rates of spillover of noradrenaline to plasma (9.11 +/- 1.12 vs. 3.39 +/- 0.26 nmol/min, p < 0.01), with rates being higher in those patients in whom hydrocephalus developed (11.15 +/- 1.40 vs. 7.90 +/- 1.41 nmol/min, p = 0.05). The degree of sympathetic nervous activation tended to be higher in females compared with males. Lower cerebral perfusion pressures were observed in those patients in whom cerebrospinal fluid concentrations of noradrenaline and dopamine metabolites were high. A marked sympathetic nervous activation, more pronounced in women and in those with hydrocephalus, occurs following subarachnoid haemorrhage. The diminished cerebral perfusion seen following subarachnoid bleeding may occur as a result of activation of central catecholaminergic neurones.
Department of Clinical Physiology, Sahlgrenska University Hospital, Gothenbourg, Sweden. gavin.lambert@baker.edu.au
Gavin
G
Lambert
Silvana
S
Naredi
Elisabeth
E
Edén
Bertil
B
Rydenhag
Peter
P
Friberg
D015102:3,4-Dihydroxyphenylacetic Acid / Q000097:blood; D000328:Adult; D000368:Aged; D015306:Biogenic Monoamines / Q000097:blood* / Q000134:cerebrospinal fluid; D006259:Craniocerebral Trauma / Q000097:blood / Q000134:cerebrospinal fluid; D004295:Dihydroxyphenylalanine / Q000097:blood; D004298:Dopamine / Q000097:blood / Q000134:cerebrospinal fluid; D004837:Epinephrine / Q000097:blood / Q000134:cerebrospinal fluid; D005260:Female; D006719:Homovanillic Acid / Q000134:cerebrospinal fluid; D006801:Humans; D006849:Hydrocephalus / Q000097:blood* / Q000134:cerebrospinal fluid; D006897:Hydroxyindoleacetic Acid / Q000134:cerebrospinal fluid; D008297:Male; D008734:Methoxyhydroxyphenylglycol / Q000031:analogs & derivatives* / Q000097:blood / Q000134:cerebrospinal fluid; D008875:Middle Aged; D009638:Norepinephrine / Q000097:blood / Q000134:cerebrospinal fluid; D012737:Sex Factors; D013345:Subarachnoid Hemorrhage / Q000097:blood* / Q000134:cerebrospinal fluid; D013564:Sympathetic Nervous System / Q000378:metabolism*
D015306:Biogenic Monoamines; D015102:3,4-Dihydroxyphenylacetic Acid; D008734:Methoxyhydroxyphenylglycol; D006897:Hydroxyindoleacetic Acid; D004295:Dihydroxyphenylalanine; C010117:3,4-dihydroxyphenylglycol; D004298:Dopamine; D009638:Norepinephrine; D006719:Homovanillic Acid; D004837:Epinephrine