The identification and specific role of the neurotransmitters involved in the central neural control of the circulation in perturbations such as exercise are topics of much experimentation and controversy at the present time. Resolution of these issues is important because our understanding of the central neural events behind autonomic control is incomplete without this information. Furthermore, the application of these data may lead to revisions in the pharmacological strategies for treatment of cardiovascular diseases. Some of the most critical areas of the central nervous system which participate in blood pressure (BP) and heart rate (HR) regulation are: 1) the intermediolateral cell column (IML) containing the cell bodies of the preganglionic sympathetic neurons and 2) various medullary areas, including the ventrolateral medulla (VLM), the raphe nuclei (RN) and the parapyramidal region of the,ventromedial medulla (VMM) which in turn are major medullary outflow pathways to the IML. The nature of chemical transmission within these areas are the focus of this proposal. It is a matter of common everyday experience that BP and HR are raised during exercise. This research will study models of neural mechanisms thought underlie these changes during exercise. One model is centrally mediated, relying on stimulation of the higher centers such as the hypothalamus to raise BP and HR. The other, the primary focus of this proposal, is a model of reflex mechanisms in exercise responses- stimulation of the ventral roots to induce muscular contraction (VRSMC), which in turn raises BP and HR. It is also important to study the transmitters mediating the reciprocal action (depressor) of the baroreceptor reflex (baroreflex) as it is thought to be inactivated during pressor events. Thus, we also wish to monitor the chemical events during the baroreflex-to determine the transmitters released due to an isolated baroreflex input so as to be aware of the significance of any changes in these transmitters during the pressor events associated with exercise. We will identify, using microdialysis and single cell recording combined with microiontophoresis: First, which substances are increased or attenuated at the level of the IML during: 1) VRSMC, 2) baroreflex stimulation and 3) stimulation of selected brainstem sites. Second, what chemicals are increased or attenuated at selected brainstem i pressor sites during: 1) VRSMC 2) baroreflex stimulation and 3) stimulation of selected diencephalic and other brainstem sites thought to modulate pressor information.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL037400-08
Application #
2218438
Study Section
Respiratory and Applied Physiology Study Section (RAP)
Project Start
1988-02-01
Project End
1999-12-31
Budget Start
1996-01-01
Budget End
1999-12-31
Support Year
8
Fiscal Year
1996
Total Cost
Indirect Cost
Name
University of Illinois Urbana-Champaign
Department
Veterinary Sciences
Type
Schools of Veterinary Medicine
DUNS #
041544081
City
Champaign
State
IL
Country
United States
Zip Code
61820
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
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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

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