The highly potent and selective 5-HT₆ receptor antagonist SB-271046 [5-chloro-N-(4-methoxy-3-piperazin-1-yl-phenyl)-3-methyl-2-benzothiophenesulfonamide] has previously been demonstrated to improve retention significantly in a spatial water maze paradigm in adult rats. However, SB-271046 did not have any effect on task acquisition. As these apparently contradictory findings may be reconciled by a prime influence of SB-271046 on memory consolidation, the ability of this compound to reverse the discrete temporal action of a cholinergic antagonist in the 6-h period following passive avoidance training was investigated. SB-271046, given orally, by gavage, 30 min prior to training Wistar rats in a step-through, light–dark passive avoidance task, was found to reverse significantly the amnesia produced by administering scopolamine (0.8 mg/kg, intraperitoneal) in the 6-h post-training period. The effect was dose-dependent over a range of 3–20 mg/kg. Further, we investigated the cognition-enhancing effects of chronic SB-271046 administration (10 or 20 mg/kg/day; 40 days) on the acquisition and consolidation of a water maze spatial learning task in a population of 20-month-old Wistar rats with age-related learning deficits. Drug treatment progressively and significantly decreased platform swim angle and escape latencies over the five sequential trials on four consecutive daily sessions compared to vehicle-treated controls. SB-271046 also improved task recall as measured by significant increases in the searching of the target quadrant on post-training days 1 and 3, when the animals would have been substantially drug-free. This significant improvement of task recall suggests SB-271046, in addition to inducing symptomatic cognition-enhancing actions, also attenuates age-related decline in neural function.

In vitro and retrospective clinical studies suggest an association between anaesthetic technique during primary breast cancer surgery and cancer outcome. Apoptosis is an important step in the mechanism of breast cancer metastasis, but whether it is influenced by anaesthetic technique is unknown. Using serum from breast cancer surgery patients randomized to receive distinct anaesthetic techniques, we investigated its effect on apoptosis in oestrogen receptor (ER)-negative breast cancer cells in vitro. Women with biopsy-proven breast cancer were randomized to receive either propofol general anaesthesia with paravertebral analgesia (PPA) or standard sevoflurane general anaesthesia with opioid analgesia (SGA) in an ongoing, prospective clinical trial (NCT 00418457). Serum from a randomly selected subset of these patients (10 PPA and 10 SGA) who had donated 20 ml venous blood immediately before anaesthetic induction and at 1 h after operation was exposed to ER-negative MDA-MB-231 cells. Apoptosis was measured using ApoLive-Glo Multiplex Assay™. Exposure of MDA-MB-231 cells to postoperative serum of PPA patients resulted in higher luminescence ratio (apoptosis) than SGA patients, median (25–75%), 0.40 (0.35–0.43) compared with 0.22 (0.21–0.30), respectively (P=0.001). The luminescence ratio of postoperative serum from SGA was reduced compared with preoperative SGA 0.22 (0.21–0.30) compared with 0.3 (0.25–0.35) (P=0.045). Serum from patients given sevoflurane anaesthesia and opioids for primary breast cancer surgery reduces apoptosis in ER-negative breast cancer cells to a greater extent than serum from patients given propofol–paravertebral anaesthesia. Anaesthetic technique might affect the serum milieu in a manner that impacts cancer cell apoptosis, and thereby tumour metastasis.