The mechanisms involved in cardiovascular regulation, such as vascular tone, fluid volume and blood osmolarity, are quite often mediated by signals circulating in the periphery, such as angiotensin II and sodium concentration. Research has identified areas within the lamina terminalis (LT), specifically the sensory circumventricular organs (CVOs), the subfornical organ and the organum vasculosum of the lamina terminalis, as playing crucial roles detecting and integrating information derived from these circulating signals. The median preoptic nucleus (MnPO) is a third integrative structure within the LT that influences cardiovascular homeostasis, although to date, its role is not as clearly elucidated. More recent studies have demonstrated that the CVOs are not only essential in the detection of traditional cardiovascular signals but also signals primarily considered to be important in the regulation of metabolic, reproductive and inflammatory processes that have now also been implicated in cardiovascular regulation. In this review, we highlight the critical roles played by the LT in the detection and integration of circulating signals that provide critical feedback control information contributing to cardiovascular regulation.

Variability exists regarding the surgical technique in breast conservation therapy. The purpose of this project was to determine differences between single (SH) or flanking (FH) hooked needle localization wires used for nonpalpable breast lesions. We retrospectively reviewed 201 female patients at a single institution from 2004 to 2008. All patients had biopsy-proven ductal carcinoma in situ or invasive disease. Comparisons were made in regard to margin status, reoperation, completion mastectomy, size of lesion, and breast specimen volume. SH was placed in 122 patients (61%) and FH in 79 patients (39%). In SH, 23 patients (18%) had positive margins and 31 patients (25%) had reoperations as compared with 31 patients (25%) with positive margin and 36 patients (44%) in the FH cohort ( P = 0.039 and 0.0037). Average lesion size and volume resected was 1.5 cm and 137 cm3 in SH and 2.85 cm and 188 cm3 in FH, respectively ( P = 0.0001 and 0.006). Positive margins were associated with lesion size and not volume of tissue excised. The FH technique was associated with more positive margins, reoperation, and completion mastectomy.

Brain‐derived neurotrophic factor (BDNF), a neurotrophin traditionally associated with neural plasticity, has more recently been implicated in fluid balance and cardiovascular regulation. It is abundantly expressed in both the central nervous system (CNS) and peripheral tissue, and is also found in circulation. Studies suggest that circulating BDNF may influence the CNS through actions at the subfornical organ (SFO), a circumventricular organ (CVO) characterized by the lack of a normal blood–brain barrier (BBB). The SFO, well‐known for its involvement in cardiovascular regulation, has been shown to express BDNF mRNA and mRNA for the TrkB receptor at which BDNF preferentially binds. This study was undertaken to determine if: (1) BDNF influences the excitability of SFO neurons in vitro; and (2) the cardiovascular consequences of direct administration of BDNF into the SFO of anesthetized rats. Electrophysiological studies revealed that bath application of BDNF (1 nmol/L) influenced the excitability of the majority of neurons (60%, n = 13/22), the majority of which exhibited a membrane depolarization (13.8 ± 2.5 mV, n = 9) with the remaining affected cells exhibiting hyperpolarizations (−11.1 ± 2.3 mV, n = 4). BDNF microinjections into the SFO of anesthetized rats caused a significant decrease in blood pressure (mean [area under the curve] AUC = −364.4 ± 89.0 mmHg × sec, n = 5) with no effects on heart rate (mean AUC = −12.2 ± 3.4, n = 5). Together these observations suggest the SFO to be a CNS site at which circulating BDNF could exert its effects on cardiovascular regulation.

Prolactin (PRL) is a peptide hormone that performs over 300 biological functions, including those that require binding to prolactin receptor (PRL-R) in neurones within the central nervous system (CNS). To enter the CNS, circulating PRL must overcome the blood-brain barrier. Accordingly, areas of the brain that do not possess a blood-brain barrier, such as the subfornical organ (SFO), are optimally positioned to interact with systemic PRL. The SFO has been classically implicated in energy and fluid homeostasis but has the potential to influence oestrous cyclicity and gonadotrophin release, which are also functions of PRL. We aimed to confirm and characterise the expression of PRL-R in the SFO, as well as identify the effects of PRL application on membrane excitability of dissociated SFO neurones. Using a quantitative real-time polymerase chain reaction, we found that PRL-R mRNA in the SFO of male and female Sprague Dawley rats did not significantly differ between juvenile and sexually mature rats (P = .34), male and female rats (P = .97) or across the oestrous cycle (P = .54). Patch-clamp recordings were obtained in juvenile male rats to further investigate the actions of PRL at the SFO. Dissociated SFO neurones perfused with 1 μmol L PRL resulted in 2 responsive subpopulations of neurones; 40% depolarised (n = 15/43, 11.3 ± 1.7 mV) and 14% hyperpolarised (n = 6/43, -6.7 ± 1.4 mV) to PRL application. Within the range of 10 pmol L to 1 μmol L , the concentrations of PRL were not significantly different in either the magnitude (P = .53) or proportion (P = .19) of response. Furthermore, PRL application significantly reduced the transient K current in 67% of SFO neurones in voltage-clamp configuration (n = 6/9, P = .02). The stability in response to PRL and expression of PRL-R in the SFO suggests that PRL function is conserved across physiological states and circulating PRL concentrations, prompting further investigations aiming to clarify the nature of PRL function in the SFO.

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