Alcohol diminishes the baro (presso) reflex by interacting with receptors in the brain stem, i.e. nucleus tractus solitarii and rostral ventrolateral medulla
[43]
. Other inves-
tigators reported that baroreceptor reflex curves, which
indicate the gain in baroreceptor reflex sensitivity, were
shifted up and reduced slope in ethanol fed rats when
challenged with vasoconstrictors (phenylephrine and
angiotensin Ⅱ) compared with controls
[45]
. This findings
and others
[42,46,47]
suggest the impairment of barorecep-
tor control and sympathetic system. A greater decrease in
heart rate in ethanol treated rats compared with control
rats during β-adrenoreceptor blockade with propranolol
indicates that the ethanol treated rats had an increased
sympathetic activity. An increase in sympathetic activity is consistent with impairment of the baroreceptors
that, when activated, inhibit the sympathetic nervous
system[45,47]
. However this mechanism is implicated more
likely in acute alcohol-induced hypertension