  Let us consider an initial data $v_0$ for the classical 3D Navier-Stokes
equation with vorticity belonging to $L^{\frac 32}\cap L^2$.
  We prove that if the solution associated with $v_0$ blows up at a finite time
$T^\star$, then for any $p\in]4,\infty[,~q_1\in[1,2[,~\mu>0,
~q_2\in\bigl[2,\bigl(1/p+\mu\bigr)^{-1}\bigr[,~\kappa\in ]1,\infty[$, and any
unit vector $e$, the $L^p$ estimate in time of
$\bigl\|(v(t)|e)_{\mathbb{R}^3}\bigr\|_{L^{\frac{3p}{p-2}}}^p
+\bigl\|(v(t)|e)_{\mathbb{R}^3}\bigr\|^p_{
\bigl(\dot{B}^{\mu+\frac2p+\frac2{q_1}-1}_{q_1,\kappa}\bigr)_{\rm h}
\bigl(\dot{B}^{\frac1{q_2}-\mu}_{q_2,\kappa}\bigr)_{\rm v}}$ blows up at
$T^\star$.
