title: Acupuncture Affects Autonomic and Endocrine but Not Behavioural Responses Induced by Startle in Horses.
abstract: Startle is a fast response elicited by sudden acoustic, tactile, or visual stimuli in a variety of animals and in humans. As the magnitude of startle response can be modulated by external and internal variables, it can be a useful tool to study reaction to stress. Our study evaluated whether acupuncture can change cardiac autonomic modulation (heart rate variability); and behavioural (reactivity) and endocrine (cortisol levels) parameters in response to startle. Brazilian Sport horses (n = 6) were subjected to a model of startle in which an umbrella was abruptly opened near the horse. Before startle, the horses were subjected to a 20-minute session of acupuncture in acupoints GV1, HT7, GV20, and BL52 (ACUP) and in nonpoints (NP) or left undisturbed (CTL). For analysis of the heart rate variability, ultrashort-term (64 s) heart rate series were interpolated (4 Hz) and divided into 256-point segments and the spectra integrated into low (LF; 0.01-0.07 Hz; index of sympathetic modulation) and high (HF; 0.07-0.50 Hz; index of parasympathetic modulation) frequency bands. Acupuncture (ACUP) changed the sympathovagal balance with a shift towards parasympathetic modulation, reducing the prompt startle-induced increase in LF/HF and reducing cortisol levels 30 min after startle. However, acupuncture elicited no changes in behavioural parameters.
authors.affiliation: Department of Physiological Sciences, Federal Rural University of Rio de Janeiro, BR 465, KM 7, 23890 000 Seropédica, RJ, Brazil.
authors.forename: Julia Dias
authors.initials: JD
authors.lastname: Villas-Boas
authors.affiliation: Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo, 14049-900 Ribeirão Preto, SP, Brazil.
authors.forename: Daniel Penteado Martins
authors.initials: DP
authors.lastname: Dias
authors.affiliation: Veterinary Institute, Federal Rural University of Rio de Janeiro, BR 465, KM 7, 23890 000 Seropédica, RJ, Brazil.
authors.forename: Pablo Ignacio
authors.initials: PI
authors.lastname: Trigo
authors.affiliation: Department of Physiological Sciences, Federal Rural University of Rio de Janeiro, BR 465, KM 7, 23890 000 Seropédica, RJ, Brazil.
authors.forename: Norma Aparecida Dos Santos
authors.initials: NA
authors.lastname: Almeida
authors.affiliation: Veterinary Institute, Federal Rural University of Rio de Janeiro, BR 465, KM 7, 23890 000 Seropédica, RJ, Brazil.
authors.forename: Fernando Queiroz
authors.initials: FQ
authors.lastname: de Almeida
authors.affiliation: Department of Physiological Sciences, Federal Rural University of Rio de Janeiro, BR 465, KM 7, 23890 000 Seropédica, RJ, Brazil ; Multicenter Post-Graduation Program in Physiological Sciences, Brazilian Society of Physiology, 05508 000 São Paulo, SP, Brazil ; Post-Graduation Program in Veterinary Medicine and Post-Graduation Program in Physiological Sciences, Federal Rural University of Rio de Janeiro, 23890 000 Seropédica, RJ, Brazil.
authors.forename: Magda Alves
authors.initials: MA
authors.lastname: de Medeiros