Reflex control of the cutaneous circulation is both of thermoregulatory and of non-thermoregulatory origin and occurs via sympathetic vasoconstrictor and sympathetic active vasodilatory mechanisms. The applicant has previously shown that each of these 2 efferent systems is subject to control by internal temperature, skin temperature, exercise-associated reflexes, and baroreflexes. Steroidal changes accompanying the phases of the menstrual cycle are known to act as background modifiers of the thermoregulatory control of skin blood flow. The PI's working hypothesis is that in the luteal phase, progesterone inhibits active vasodilation by shifting to a higher internal temperature threshold for its initiation and elevates vasoconstrictor activity for any given body temperature as well. Elevated estrogen levels in the ovulatory phase are hypothesized to have directionally opposite effects on vasoconstriction and active vasodilator function. Through selective local blockade of vasoconstrictor function the applicant will examine changes in active vasodilator function among menstrual phases. Such effects would provide mechanisms for the well-documented phasic changes in basal internal temperature and in the control of the cutaneous circulation through the menstrual cycle. The applicant will also seek evidence for the roles of progesterone and estrogen in these phasic changes by taking advantage of the normal fluctuations of steroid levels among follicular (both low), ovulatory (estrogen elevated), and luteal (both elevated) phases to find how those hormonal patterns affect the control of the vasodilator and vasoconstrictor pathways. These studies will be complemented by examinations of alterations in control of the vasoconstrictor and vasodilator pathways between active and placebo phases of oral contraceptives. The applicant will evaluate peripheral contributions by these steroids in vasomotor function by testing whether vasoconstrictor responses to controlled application of norepinephrine or vasodilator responses to direct application of acetylcholine are dependent on the phase of the menstrual cycle. This question will be further addressed by finding if the level of skin blood flow in areas free of autonomic influences (via cutaneous nerve block) and in areas with intact innervation vary among phases of the menstrual cycle or between phases of oral contraceptive use. The role of prostaglandin synthesis in the upward shift of the thermoregulatory control of the active vasodilator system will also be evaluated.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
1R01HL059166-01A1
Application #
2695327
Study Section
Respiratory and Applied Physiology Study Section (RAP)
Project Start
1998-08-14
Project End
2003-07-31
Budget Start
1998-08-14
Budget End
1999-07-31
Support Year
1
Fiscal Year
1998
Total Cost
Indirect Cost
Name
University of Texas Health Science Center San Antonio
Department
Physiology
Type
Schools of Medicine
DUNS #
800772162
City
San Antonio
State
TX
Country
United States
Zip Code
78229
Hodges, Gary J; Kellogg, Dean L; Johnson, John M (2015) Effect of skin temperature on cutaneous vasodilator response to the ?-adrenergic agonist isoproterenol. J Appl Physiol (1985) 118:898-903
Johnson, John M; Kellogg Jr, Dean L (2010) Thermoregulatory and thermal control in the human cutaneous circulation. Front Biosci (Schol Ed) 2:825-53
Johnson, John M; Kellogg Jr, Dean L (2010) Local thermal control of the human cutaneous circulation. J Appl Physiol 109:1229-38
Hodges, Gary J; Kosiba, Wojciech A; Zhao, Kun et al. (2009) The involvement of heating rate and vasoconstrictor nerves in the cutaneous vasodilator response to skin warming. Am J Physiol Heart Circ Physiol 296:H51-6
Hodges, Gary J; Chiu, Caroline; Kosiba, Wojciech A et al. (2009) The effect of microdialysis needle trauma on cutaneous vascular responses in humans. J Appl Physiol 106:1112-8
Hodges, Gary J; Johnson, John M (2009) Adrenergic control of the human cutaneous circulation. Appl Physiol Nutr Metab 34:829-39
Hodges, Gary J; Kosiba, Wojciech A; Zhao, Kun et al. (2008) The involvement of norepinephrine, neuropeptide Y, and nitric oxide in the cutaneous vasodilator response to local heating in humans. J Appl Physiol 105:233-40
Gonzalez-Alonso, Jose; Crandall, Craig G; Johnson, John M (2008) The cardiovascular challenge of exercising in the heat. J Physiol 586:45-53
Aoki, Ken; Zhao, Kun; Yamazaki, Fumio et al. (2008) Exogenous melatonin administration modifies cutaneous vasoconstrictor response to whole body skin cooling in humans. J Pineal Res 44:141-8
Hodges, Gary J; Kosiba, Wojciech A; Zhao, Kun et al. (2007) The role of baseline in the cutaneous vasoconstrictor responses during combined local and whole body cooling in humans. Am J Physiol Heart Circ Physiol 293:H3187-92

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