DOI 10.1007/s00702-005-0426-x J Neural Transm (2006) 113: 1511–1517 Inverse relationship between central serotonergic neurotransmission and blood pressure in alcohol-dependent male subjects J. Balldin 1 , M. Andersson 1 , U. Berggren 1;2 , J. Engel 3 , M. Eriksson 1 , and C. Fahlke 4 1 Sahlgrenska Academy at G€ oteborg University, Institute of Clinical Neuroscience, Section of Psychiatry, Sahlgrenska University Hospital=M€ olndal, 2 Psychiatric Clinic Kung€ alv Hospital, 3 Department of Pharmacology, Sahlgrenska Academy at G€ oteborg University, Institute of Physiology and Pharmacology 4 Department of Psychology, G€ oteborg University, G€ oteborg, Sweden Received April 9, 2005; accepted November 19, 2005 Published online February 9, 2006; # Springer-Verlag 2006 Summary. Data has accumulated indicating an inverse relation between central seroto- nergic (5-HT) neurotransmission and blood pressure in hypertensive rats and in healthy individuals. The present study aimed to eluci- date whether an inverse relation exists between systolic (SBP) and diastolic (DBP) blood pressure levels and central 5-HT neurotrans- mission also in a group of alcohol-dependent individuals. Central 5-HT neurotransmission was assessed by using the maximum pro- lactin (PRL) responses to the 5-HT probe DL-fenfluramine (DL-FEN; 60 mg po) in 17 alcohol-dependent male subjects investigated during a period of on-going alcohol intake. BP was measured immediately before all time points for blood sampling, and readings before DL-FEN administration were used as the subjects resting BP. Results showed that there were inverse correlations between the maximum PRL responses to DL-FEN and the SBP levels (r ¼0.57, p < 0.002) and with the DBP levels (r ¼0.52, p < 0.05), respec- tively. The present study suggests the exis- tence of an association between central 5-HT neurotransmission and blood pressure regula- tion also in alcohol-dependent individuals. Keywords: Alcohol-dependence, blood pres- sure, CNS, serotonin. Introduction It has previously been shown that pharmaco- logical stimulation of certain serotonin (5- hydroxytryptamine; 5-HT) receptors changes blood pressure (BP) responses in a complex way (Page, 1954). Likewise the central 5-HT neurotransmission is influenced by experi- mental manipulation of BP as shown in animal studies (Singewald et al., 1995). The conclusions of these findings suggest that the central 5-HT activity might be part of the pathogenesis of hypertension. Further evi- dence of the involvement of central 5-HT neurotransmission in hypertension in humans has recently been reported by Muldoon et al. (1998). These authors showed that in white,