Spinal cord processing of cardiac nociception: are there sex differences between male and proestrous female rats?

Studying Cardiac Neural Network Dynamics: Challenges and Opportunities for Scientific Computing

Neural control of the heart involves continuous modulation of cardiac mechanical and electrical activity to meet the organism's demand for blood flow. The closed-loop control scheme consists of interconnected neural networks with central and peripheral components working cooperatively with each other. These components have evolved to cooperate control of various aspects of cardiac function, which produce measurable "functional" outputs such as heart rate and blood pressure. In this review, we will outline fundamental studies probing the cardiac neural control hierarchy. We will discuss how computational methods can guide improved experimental design and be used to probe how information is processed while closed-loop control is operational. These experimental designs generate large cardio-neural datasets that require sophisticated strategies for signal processing and time series analysis, while presenting the usual large-scale computational challenges surrounding data sharing and reproducibility. These challenges provide unique opportunities for the development and validation of novel techniques to enhance understanding of mechanisms of cardiac pathologies required for clinical implementation.

Comparison of pain threshold and duration of pain perception in men and women of different ages

Introduction Pain is a sensory and emotional experience that occurs with the presence of tissue injury, actual or potential. Pain is subjective, and its expression is primarily determined by the perceived intensity of the painful sensation, called the pain threshold. Objective To evaluate whether there are differences in pain threshold (LD) and time to pain perception (TPED) between the gender in different age groups and to analyze the correlation between age and pain threshold in each gender. Methods and procedures Participants were 60 volunteers divided into 6 groups (n = 10 each) according to gender and age (18–33, 34–49, and 50–64 years). The evaluation of perception and pain tolerance was performed by immersing the container with one hand in water at a temperature of 0 °C–2 °C; the latency to withdrawal of the hand from ice water was measured in seconds and was considered a measure of LD. The TPED was reported by each participant as the start time of the painful stimulus. Results We found differences between the LD for G1 (men aged between 18 and 33 years) and G2 (women aged 18 to 33 years) with greater LD for G1 (p = 0.0122) and greater LD for women (p = 0.0094); for other comparisons of LD and TPED, there were no differences (p > 0.05 for all comparisons). Low correlation was found between age progression with increased LD and the TPED only in men (p = 0.01 and r = 0.45 and p = 0.05 and r = 0.34, respectively). Conclusion We conclude that women have a higher pain threshold than men especially when these groups are aged between 18 and 33 years, and in men increasing age correlates with increased TPED and LD.

Sex differences and hormonal modulation of deep tissue pain

Women disproportionately suffer from many deep tissue pain conditions. Experimental studies show that women have lower pain thresholds, higher pain ratings and less tolerance to a range of painful stimuli. Most clinical and epidemiological reports suggest female gonadal hormones modulate pain for some, but not all, conditions. Similarly, animal studies support greater nociceptive sensitivity in females in many deep tissue pain models. Gonadal hormones modulate responses in primary afferents, dorsal horn neurons and supraspinal sites, but the direction of modulation is variable. This review will examine sex differences in deep tissue pain in humans and animals focusing on the role of gonadal hormones (mainly estradiol) as an underlying component of the modulation of pain sensitivity.