since the alpha-adrenergic blocking agent phenoxybenzamine blocks the effect of clonidine on type 3 tucking behavior , whereas the beta-adrenergic blocker propranolol does not , we suggest that tucking and the attainment of the hatching position are mediated by an alpha-adrenergic mechanism in the brain and/or spinal cord .
C0004927
behavior
C0006104
brain