Posttraumatic Stress Disorder Disturbs Coronary Tone and Its Regulatory Mechanisms

Abstract

Posttraumatic stress disorder (PTSD) is associated with myocardial injury, but changes in coronary regulatory mechanisms in PTSD have not been investigated. This study evaluated the effect of PTSD-inducing stress on coronary tone and its regulation by nitric oxide (NO) and voltage-gated K channels. PTSD was induced by exposing rats to predator stress, 15 min daily for 10 days, followed by 14 stress-free days. Presence of PTSD was confirmed by the elevated plus-maze test. Coronary tone was evaluated from changes in coronary perfusion pressure of Langendorff isolated hearts. Predator stress induced significant decreases in coronary tone of isolated hearts and in blood pressure of intact rats. L-NAME, a non-selective NO synthase (NOS) inhibitor, but not S-MT, a selective iNOS inhibitor, and increased coronary tone of control rats. In PTSD rats, both L-NAME and S-MT increased coronary tone. Therefore, the stress-induced coronary vasodilation resulted from NO overproduction by both iNOS and eNOS. NOS induction was apparently due to systemic inflammation as evidenced by increased serum interleukin-1β and C-reactive protein in PTSD rats. Decreased corticosterone in PTSD rats may have contributed to inflammation and its effect on coronary tone. PTSD was also associated with voltage-gated K channel dysfunction, which would have also reduced coronary tone.

Chronic predator scent stress alters serotonin and dopamine levels in the rat thalamus and hypothalamus, respectively

“…The decrease in animals AI after chronic PSS, observed two weeks after the last exposure to the stressor, is similar to this reported in our previous studies (Lazuko et al 2018;Manukhina et al 2018). Our funding on the altered 5-HT transmission in the thalamus is consistent with previous studies by other groups.…”

“…Repeated exposure of the rats to the predator scent stress (PSS) has been used in our previous studies as an animal model of post-traumatic stress disorder (PTSD). We had previously reported that repeated PSS induce long-lasting behavioral changes, such as increased anxiety index (AI), observed as late as fourteen days after the last PSS exposure (Lazuko et al 2018;Manukhina et al 2018). Repeated PSS might be a more accurate model for PTSD than the acute one, since it minimizes the effect of uncontrolled factors, such as concentration of pheromones in each individual dose of urine.…”

Hexobarbital Sleep Test for Predicting the Susceptibility or Resistance to Experimental Posttraumatic Stress Disorder

“…Unstressed rats rested throughout this period. The stressed subgroups were exposed to cat urine scent (PSS) for 10 min daily for 10 days followed by 14 days of rest under stress-free conditions [ 24 ].…”

Intermittent Hypoxic Conditioning Alleviates Post-Traumatic Stress Disorder-Induced Damage and Dysfunction of Rat Visceral Organs and Brain

“…To induce PTSD, we used a modified model of predator stress that was initially described by Cohen and Zohar [79] and as used in our prior studies [18,80]. Predator stress was accomplished by exposing rats of the PTSD group to cat urine scent for 15 min daily for 10 days.…”