There is extensive evidence that activation of the immune system is both necessary and required for the development of angiotensin II (Ang II)-induced hypertension in males. The purpose of this study was to determine whether sex differences exist in the ability of the adaptive immune system to induce Ang II-dependent hypertension and whether central and renal T-cell infiltration during Ang II-induced hypertension is sex dependent. Recombinant activating gene-1 (Rag-1)(-/-) mice, lacking both T and B cells, were used. Male and female Rag-1(-/-) mice received adoptive transfer of male CD3(+) T cells 3 weeks before 14-day Ang II infusion (490 ng/kg per minute). Blood pressure was monitored via tail cuff. In the absence of T cells, systolic blood pressure responses to Ang II were similar between sexes (Δ22.1 mm Hg males versus Δ18 mm : Hg females). After adoptive transfer of male T cells, Ang II significantly increased systolic blood pressure in males (Δ37.7 mm : Hg; P
The effect of prolonged aortic depressor nerve (ADN) stimulation on carotid sinus baroreflex regulation of arterial pressure (AP) and renal sympathetic nerve activity (RSNA) was examined in anesthetized rabbits. Ramp increases in carotid sinus pressure (CSP) were repeated before and after 5 min of bilateral ADN stimulation. One minute after ADN stimulation the curve relating AP to CSP had shifted up and to the right, characterized by significant increases (P
The purpose of the present study was to describe, at the single-channel level, the activity of a calcium-sensitive potassium channel in rat visceral-sensory neurons which has been suggested to be involved in sensory neuron excitability. Single-channel recordings in the inside-out configuration identified a 220 pS conductance calcium-activated potassium channel (KCa). From a -20 mV holding potential, increasing [Ca2+]i from 0.01 microM to 1.0 microM increased the open probability of this channel 92% (from 0.12 to 0.23). However, from a +20 mV holding potential, increasing [Ca2+]i from 0.01 to 1.0 microM increased the open probability by 326% (from 0.15 to 0.64). In addition, this large conductance KCa channel was blocked by TEA (1.0 microM) and charybdotoxin (40 microM) when applied to the external surface. These results are the first to characterize a large conductance KCa channel in the sensory afferent neurons of the rat nodose ganglia and should further expand the understanding of the ionic currents involved in the regulation of sensory afferent neuronal activity.