Abstract

Isometric muscular exercise causes increases in heart rate, blood pressure and ventilation. At least part of this response in reflexly evoked. This reflex may be conveniently studied in acute animal utilizing stimulation of cut ventral roots to achieve muscular contraction which in turn evokes a cardiovascular response similar in many ways to that observed during isometric exercise. This reflex is often called the """"""""exercise pressor reflex"""""""" as a convenient operational definition. The proposed research will investigate the specific location, electrophysiological response characteristics and immunocytochemical properties of cells which may contribute to the reflex. Brainstem areas for study include: (a) caudal ventrolateral medulla including the area in or near the lateral reticular nucleus (LRN) and the nucleus ambiguus (NA), (b) rostral ventrolateral medulla including the areas analogous to the C1 areas in the rat, and (c) medial medulla including the """"""""dorsomedial pressor region"""""""", the nucleus of the tractus solitarius and the inferior olive. The cells of these areas will be evaluated for responses to: (1) muscular contraction, (2) baroreceptor input, (3) chemoreceptor input, (4) stimulation of the """"""""subthalamic locomotor area"""""""", or """"""""defence area"""""""", and also will be evaluated for (5) contribution to tonic sympathetic outflow, and (6) epinephrine and norepinephrine content. It is though that a fundamental reciprocal inhibition relationship might exist between the muscular contraction- evoked pressor reflex and various depressor reflexes; and therefore, key points in both types of reflexes will be studied. The main analysis techniques will include the use of 1) single cell electrical recording 2) immunocytochemical labelling for tyrosine hydroxylase (TH) and phenylethanolamine-N- methyltransferase (PNMT). The studies will yield a further understanding of processes underlying pressor reflexes and their reciprocal relationship with depressor reflexes.

  Funding Agency

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
1R01HL037400-01
Application #
3353017
Study Section
Respiratory and Applied Physiology Study Section (RAP)
Project Start
1987-09-01
Project End
1988-01-31
Budget Start
1987-09-01
Budget End
1988-01-31
Support Year
1
Fiscal Year
1987
Total Cost
Indirect Cost

  Institution

Name
University of Texas Sw Medical Center Dallas
Department
Type
Schools of Medicine
DUNS #
City
Dallas
State
TX
Country
United States
Zip Code
75390

  Publications

Nelson, Amanda J; Juraska, Janice M; Ragan, Brian G et al. (2010) Effects of exercise training on dendritic morphology in the cardiorespiratory and locomotor centers of the mature rat brain. J Appl Physiol 108:1582-90
Ragan, Brian G; Nelson, Amanda J; Bell, Gerald W et al. (2007) Salicylate-based analgesic balm attenuates pressor responses from skeletal muscle. Med Sci Sports Exerc 39:1942-8
Nelson, Amanda J; Juraska, Janice M; Musch, Timothy I et al. (2005) Neuroplastic adaptations to exercise: neuronal remodeling in cardiorespiratory and locomotor areas. J Appl Physiol 99:2312-22
Ragan, Brian G; Nelson, Amanda J; Foreman, Jonathan H et al. (2004) Effects of a menthol-based analgesic balm on pressor responses evoked from muscle afferents in cats. Am J Vet Res 65:1204-10
Nelson, Amanda J; Ragan, Brian G; Bell, Gerald W et al. (2004) Capsaicin-based analgesic balm decreases pressor responses evoked by muscle afferents. Med Sci Sports Exerc 36:444-50
Ichiyama, Ronaldo M; Waldrop, Tony G; Iwamoto, Gary A (2004) Neurons in and near insular cortex are responsive to muscular contraction and have sympathetic and/or cardiac-related discharge. Brain Res 1008:273-7
Ichiyama, Ronaldo M; Gilbert, Andrea B; Waldrop, Tony G et al. (2002) Changes in the exercise activation of diencephalic and brainstem cardiorespiratory areas after training. Brain Res 947:225-33
Swiatkowski, K; Dellamano, L M; Vissing, J et al. (1999) Differential effects from parapyramidal region and rostral ventrolateral medulla mediated by substance P. Am J Physiol 277:R1120-9
Gulani, V; Iwamoto, G A; Jiang, H et al. (1997) A multiple echo pulse sequence for diffusion tensor imaging and its application in excised rat spinal cords. Magn Reson Med 38:868-73
Iwamoto, G A; Waldrop, T G (1996) Lateral tegmental field neurons sensitive to muscular contraction: a role in pressor reflexes? Brain Res Bull 41:111-20

Showing the most recent 10 out of 17 publications